JP6026612B2 - Control device for internal combustion engine for vehicle - Google Patents

Description

  The present invention relates to a control device for a vehicle internal combustion engine in a vehicle having an internal combustion engine and a vehicle drive system, and particularly for a vehicle improved so as to obtain a suitable acceleration response characteristic for a given target torque. The present invention relates to a control device for an internal combustion engine.

  When the accelerator pedal is depressed or when the engine crank end torque changes suddenly when the fuel cut is restored, torsional vibrations occur in the vehicle drive system including the engine, transmission, drive shaft and tires. In some cases, the vibration (vehicle turning back) occurs. In order to prevent this, normally, control (smoothing control) that applies a first-order low-pass filter to target engine torque given by an accelerator pedal or the like, or control that limits increment of the target engine torque per predetermined time (Δ amount) Limit control).

  As a result, although the vibration of the vehicle longitudinal acceleration is avoided, there is a problem that the acceleration performance of the vehicle is impaired and the impression of the vehicle is damaged.

  Patent Document 1 discloses a technique for suppressing the occurrence of vibration when the accelerator pedal is depressed by feedback-correcting a predicted vibration component with respect to a target torque correlation value that sets an output torque of a vehicle engine. ing. Patent Document 1 discloses, as a conventional technique, a throttle opening is controlled using a compensator having an inverse function of a transfer function of a model of a vehicle drive system, or the throttle opening is increased in two stages. It also mentions techniques for obtaining similar results. However, a considerable error is expected to occur between the target torque correlation value and the actual torque value, and there is a question as to whether proper control can always be realized.

  Japanese Patent Laid-Open No. 2004-26883 discloses a difference between a torque (T0) corrected so as not to generate vehicle vibration and a predicted torque (Te) obtained from an intake manifold pressure Pm and an engine speed N based on a torque map based on an ignition timing. The method of correcting by is disclosed. However, since the predicted torque (Te) is calculated using the actual intake manifold pressure (Pm) and the engine speed (N), the predicted torque does not always accurately represent the actual torque due to the influence of sensor error or the like. There are still problems similar to the above. Further, since the adjustment of the output torque is performed by adjusting the ignition timing, there is a possibility that sufficient responsiveness cannot be obtained.

  In order to precisely control such vibration acceleration characteristics of the vehicle, it is necessary to accurately predict or estimate the acceleration response of the vehicle to the accelerator pedal. In general, the engine intake amount can be estimated from the throttle opening, and the engine output torque can be calculated from the estimated intake amount. However, it is difficult to accurately control the acceleration response of the vehicle with respect to the accelerator pedal due to individual differences in the throttle valve and changes over time.

  In addition, it is conceivable that an airflow sensor is provided in the intake system of the engine, the actual intake amount of the engine is obtained, and the acceleration characteristics of the engine are controlled based on this, but the response characteristic of the airflow sensor has a considerable time delay and dead time. Accordingly, it is not realistic to control the acceleration characteristics of the engine in real time based on the output of the air flow sensor. Patent Document 3 discloses an intake parameter calculation device that calculates an actual intake air amount by correcting a basic intake air amount detected by an air flow sensor based on various intake parameters.

Japanese Patent Laid-Open No. 2004-068702 Japanese Patent Laid-Open No. 2005-054645 WO2011 / 132464 A1

  In view of the problems of the prior art, a main object of the present invention is to provide a control device for an internal combustion engine for a vehicle that can be smoothly accelerated even when the target torque is suddenly increased. .

  A second object of the present invention is to provide a control device for an internal combustion engine for a vehicle that can accurately adjust the output torque of the internal combustion engine and suitably suppress vibrations of the vehicle drive system.

  A third object of the present invention is to accurately estimate an output torque of an internal combustion engine with respect to a given target torque even in the case of individual differences and / or aging in an engine throttle or other intake system elements, An object of the present invention is to provide a control device for an internal combustion engine for a vehicle that can suitably suppress the vibration of the vehicle.

  In order to achieve such an object, the present invention provides a control apparatus for an internal combustion engine for a vehicle in a vehicle having an internal combustion engine and a vehicle drive system, wherein the target torque is set for setting the target torque of the internal combustion engine. A target torque correcting unit that corrects the target torque to a corrected target torque, and an output torque that is provided to the internal combustion engine to be generated by the internal combustion engine according to the corrected target torque. The target torque correction unit includes a first filter processing unit that expresses a response delay of the internal combustion engine and a second filter processing unit that suppresses vibration of the vehicle drive system. A control apparatus is provided.

  According to such a control apparatus for an internal combustion engine for a vehicle, it is possible to set a target torque that effectively suppresses vibration of the vehicle body and does not impair acceleration performance.

  In particular, the output torque adjustment unit forms a throttle, and a throttle model that calculates the amount of air passing through the throttle based on the opening of the throttle, an intake system model that calculates the amount of cylinder intake air from the amount of air that passes through the throttle, and cylinder intake air Based on the deviation between the predicted target torque and the predicted torque using the engine torque model that calculates the engine generated torque from the quantity, and the deviation between the corrected target torque and the predicted torque, the deviation is eliminated. It is preferable to have an ignition timing adjusting unit that adjusts the ignition timing of the internal combustion engine.

  Thereby, it is possible to more effectively suppress the vibration of the vehicle body.

  According to a preferred embodiment of the present invention, the first filter processing unit forms an inverse function of a second-order lag transfer function determined according to a gear ratio or a gear position of the vehicle drive system, and The filter processing unit forms a second-order lag transfer function.

  Thereby, an accurate target torque can be set, and a large amount of data or calculation amount is not required.

  Although the throttle opening can be detected using a throttle sensor, the actual throttle opening is estimated by using the target throttle opening and the throttle model set for the output of the target torque setting unit. You can also.

  Thereby, the throttle sensor can be dispensed with, and the wiring leading to the throttle sensor can be dispensed with.

  According to an aspect of the present invention, the control device of the present invention includes an air flow meter, an air flow meter model that calculates an output of the air flow meter based on an output of the throttle model, an output of the air flow meter, and the air flow meter Throttle passage air amount correction means for correcting the output of the throttle model based on the model output to estimate the actual throttle passage air amount is further provided.

  As a result, the output torque of the internal combustion engine can always be accurately controlled regardless of individual differences in the throttle and aging.

  In particular, when the throttle passage air amount correction means has a first-order lag element to be applied to the output, a smooth control action can be realized.

  The throttle passage air amount correcting means updates the throttle model at a predetermined timing based on the output of the air flow meter and the output of the air flow meter model, thereby correcting the throttle passage air amount on a long-term basis. At the same time, it can be performed in a short time, and the output torque of the internal combustion engine can always be accurately controlled.

  As described above, according to the present invention, even when the target torque is suddenly increased, the vehicle can be accelerated smoothly, and the output torque of the internal combustion engine can be adjusted accurately, and the vibration of the vehicle drive system can be suitably adjusted. Can be suppressed.

Schematic diagram showing a model of a vehicle drive system in the present invention Diagram showing filter processing in the present invention Functional block diagram of a control device for an internal combustion engine for a vehicle based on the present invention Functional block diagram showing details of the throttle model shown in FIG. Functional block diagram showing details of the first error correction value calculator shown in FIG. Functional block diagram showing details of the second error correction value calculator shown in FIG. Functional block diagram showing the configuration for estimating the throttle opening from the target torque Graph comparing vehicle acceleration response in the present invention and prior art

  Embodiments of a control device for an internal combustion engine for a vehicle according to the present invention will be described below in detail with reference to the drawings.

ここで用いられている文字の意味は以下の通りである。
I_E[kgm²]: エンジン系慣性モーメント
θ_k[rad]: エンジン回転角
I_B[kgm²]: 車体系慣性モーメント
θ_B[rad]: 車体側回転角
T_E[Nm]: エンジントルク
K_D[Nm/rad]: ドライブシャフト剛性
C_E[Nm/(rad/s)]: エンジン回転系減衰係数
C_D[Nm/(rad/s)]: ドライブシャフト減衰係数
C_T[Nm/(rad/s)]: 車輪（タイヤ）減衰係数
i: 最終段までの減速比 The vehicle drive system can be expressed by a model as shown in FIG. 1, and the following equation of motion can be established.

The meanings of the characters used here are as follows.
I _E [kgm ² ]: Engine system moment of inertia θ _k [rad]: Engine rotation angle
I _B [kgm ² ]: Vehicle system inertia moment θ _B [rad]: Vehicle body side rotation angle
T _E [Nm]: Engine torque
K _D [Nm / rad]: Drive shaft rigidity
C _E [Nm / (rad / s)]: Engine rotation system damping coefficient
C _D [Nm / (rad / s)]: Drive shaft damping coefficient
C _T [Nm / (rad / s)]: Wheel (tire) damping coefficient
i: Reduction ratio to the final stage

更に、以下の３つのパラメータをギヤ比又は各変速段で同定する。
K ：振幅ゲイン
ω_n：固有振動数
ζ：減衰係数 The coefficients of these equations of motion can be obtained by a known identification method. This equation of motion, it is possible to determine the transfer characteristic from the engine torque T _E to the vehicle acceleration d ² θB / dt ² as follows.

Further, the following three parameters are identified by the gear ratio or each gear position.
K: amplitude gain ω _n : natural frequency ζ: damping coefficient

  In a drive-by-wire vehicle, a required torque for the engine, that is, a target torque is set by a throttle depression amount. As described above, since the vehicle drive system is a spring mass system with relatively little damping force, in a conventional vehicle, when the throttle is depressed relatively abruptly, as shown by a thin line in FIG. In some cases, the acceleration response of the motor is vibrated with overshoot. In order to avoid such a problem, it is known to provide a first-order lag characteristic between the accelerator pedal throttles. However, as shown by the broken line in FIG. 8, the acceleration performance of the vehicle is sacrificed and satisfied. It's not a solution to a problem that can be done.

  FIG. 2 shows the filtering process in the present invention. As shown in the frequency response characteristic graph of the transfer function of the vehicle acceleration with respect to the target torque shown in the center of FIG. 2, the vehicle drive system has a peak gain in the vicinity of 4.6 Hz, which is vibrational. Cause the acceleration response of the vehicle. Therefore, an appropriate filter is arranged between the accelerator pedal throttles, the peak portion of the frequency response characteristic is flattened as shown by the arrow A, the vibrational response is suppressed, and the high frequency region is shown as shown by the arrow B. By improving the response characteristic, a quick response characteristic is realized. By making the frequency response characteristic as flat as possible over such a wide band, it is possible to avoid an oscillating vehicle acceleration response and realize a high response characteristic.

  FIG. 3 shows a control apparatus for an internal combustion engine for a vehicle configured under such consideration. This vehicle is driven by an internal combustion engine E, and the output of the internal combustion engine E is adjusted by changing the opening of a throttle 1 attached to the internal combustion engine E. In the present embodiment, the throttle 1 includes an opening degree sensor 3. An air flow meter 2 that measures the amount of intake air that passes through the throttle 1 is provided on the upstream side of the throttle 1.

  The accelerator pedal 4 is provided with a pedal sensor 4a for detecting the depression amount of the accelerator pedal, and the opening degree of the throttle 1 is set according to the output of the pedal sensor 4a. In the present embodiment, a first filter 5 and a second filter 6 are arranged in series between the pedal sensor 4 a and the throttle 1.

The transfer function of the first filter 5 is given by W (s) = 1 / (Ts + 1). This constitutes a first-order low-pass filter that models the filling delay in the intake system. The transfer function of the second filter 6 is given by an inverse function of a transfer characteristic that forms a second-order lag system from the engine torque TE to the vehicle acceleration d ² θ _B / dt ^2, that is, G ⁻¹ (s) = s ² + 2ζωns + ωn ^2. It is done. The output of the pedal sensor 4a is transmitted to the throttle 1 as a corrected target torque after such a filter is applied.

  On the other hand, the predicted torque of the internal combustion engine E is obtained from the output of the opening sensor 3 of the throttle 1. For this purpose, the output of the opening sensor 3 of the throttle 1 is first sent to the throttle model 7. In the throttle model 7, the actual passing air amount is corrected based on the passing air amount obtained by the air flow meter 2.

  FIG. 4 shows details of the throttle model 7. The output of the air flow meter 2 is input to the passing air amount estimation unit 21 together with the throttle upstream air pressure PA, the throttle downstream air pressure PB, and the passing air temperature TA. The passing air amount estimation unit 21 may form a base of the model of the throttle 1. That is, the base throttle model to be applied to the standard production model may be formed under standard conditions. Further, the throttle upstream air pressure PA can be simplified to be composed of the atmospheric pressure while ignoring the pressure loss of the air filter or the like.

  The output of the passing air amount estimation unit 21 is sent to the first error correction value calculation unit 22 together with the output of the air flow meter 2. As shown in FIG. 5, the first error correction value calculation unit 22 divides the air flow meter model 31 that receives the output of the passing air amount estimation unit 21 and the output of the air flow meter model 31 by the output of the air flow meter 2. And a first-order lag element 33 applied to the coefficient obtained by the divider 32, and a long-term correction coefficient is obtained as an output of the first-order lag element 33.

このようにして得られたロングターム補正係数は、スロットル１の経年変化のような長期的な目標トルクに対する通過空気量の応答特性の変化を補償するためのものである。 The transfer function of the air flow meter model 31 is composed of a combination of a dead time Tn and a first-order lag of the time constant Td as expressed as follows.

The long term correction coefficient obtained in this way is for compensating for the change in the response characteristic of the passing air amount with respect to the long-term target torque, such as the secular change of the throttle 1.

  The first error correction value calculation unit 22 updates the parameter of the passing air amount estimation unit 21 when the long term correction coefficient exceeds a predetermined value over a long period of time, and the long term correction coefficient is a value close to 1. To stay on. In other words, the passing air amount estimation unit 21 is appropriately updated by learning during operation, so that the passing air amount can always be estimated relatively accurately regardless of changes in the throttle 1 over time.

  The output of the passing air amount estimation unit 21 is sent to the second error correction value calculation unit 24 together with the output of the air flow meter 2. As shown in FIG. 6, the second error correction value calculation unit 24 includes an air flow meter model 34 that receives the output of the passing air amount estimation unit 21, and a division that divides the output of the air flow meter model 34 by the output of the air flow meter 2. And a first-order lag element 36 applied to the coefficient obtained by the divider 35, and a short-term correction coefficient is obtained as an output of the first-order lag element 36.

  In this case, when the output of the air flow meter 2 is pulsating or when the pressure ratio between the upstream and downstream of the throttle 1 reaches a predetermined upper limit value, the time constant of the primary delay element 36 is set to 0, and the short term Substantial correction is not performed.

  The air flow meter model 34 may be the same as the air flow meter model 31 of the first error correction value calculation unit 22. The short term correction coefficient obtained in this way is for compensating for a change in the response characteristic of the passing air amount with respect to a short-term target torque, such as a change in intake air temperature or atmospheric pressure. In particular, in the case of the present embodiment, the short term correction coefficient is applied to the output of the passing air amount estimation unit 21 updated by the first error correction value calculation unit 22. By such correction, it is possible to effectively minimize the deviation between the predicted torque and the actual torque due to sensor errors and hardware variations.

  In the present embodiment, the opening degree of the throttle 1 is detected by using the opening degree sensor 3, but the target throttle opening degree and the throttle model 7 set for the output of the pedal sensor 4a are used. Thus, the opening degree of the throttle 1 can also be estimated.

  FIG. 7 shows a configuration for estimating the opening of the throttle 1 in this way. The target torque given by the accelerator pedal is input to the vehicle inverse model 41. The vehicle inverse model 41 is also input with related data such as torque loss due to braking and gear position. The required combustion torque obtained from the vehicle inverse model 41 is input to the engine inverse model 42. Related data such as torque conversion coefficient and ignition efficiency is also input to the engine inverse model 42. The required intake air amount obtained from the engine inverse model 42 is input to the intake system inverse model 43. The intake system inverse model 43 also receives related data such as the engine speed Ne and the throttle downstream air pressure PB. The required throttle passage air amount obtained from the intake system inverse model 43 is input to the throttle inverse model 44. Relevant data such as the throttle upstream air pressure PA, the throttle downstream air pressure PB, and the passing air temperature TA are also input to the throttle inverse model 44. Finally, the estimated throttle opening is output from the throttle inverse model 44.

  As can be understood by referring to FIG. 3 again, the output of the throttle model 7 is sent to the intake system model 8, and the influence on the intake due to the inertia of intake air and the intake resistance in the intake system is taken into consideration. . Further, the output of the intake system model 8 is sent to the engine torque model 9, and a predicted torque is generated as an engine torque for a given intake flow rate.

  In the subtracter 10, the predicted torque is subtracted from the output (corrected target torque) of the second filter 6. The deviation between the predicted torque and the corrected target torque is sent to the ignition timing adjustment unit (ignition timing control unit) 11. In the ignition timing adjustment unit 11, the ignition timing controller 12 calculates an ignition timing change amount (retard amount) according to the deviation, and this is calculated by the ignition timing adjustment unit 11 in the subtractor 13. Subtract from the basic ignition timing given. The actual ignition timing obtained as a result is applied to the engine 1 and is also reflected in the engine torque model 9 at the same time. In this way, the corrected target torque can produce the expected effect regardless of the actual state of the engine or errors in the model, sensor, and the like.

  The change in the ignition timing described above is considered that the predicted torque follows the actual torque more accurately than the corrected target torque, so that the deviation between the predicted torque and the corrected target torque is eliminated. This is to change the actual torque (reduce) so that the vibration acceleration response of the vehicle can be suitably suppressed.

  In this way, the acceleration response of the vehicle to the depression of the accelerator pedal can be made quick and stable as shown by the thick line in FIG.

  Although the description of the specific embodiment is completed above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Throttle 3 Opening degree sensor 4 Accelerator pedal 4a Pedal sensor 5 1st filter 6 2nd filter 7 Throttle model (engine model)
8 Intake system model (engine model)
9 Engine torque model (engine model)
11 Ignition timing adjuster

Claims (4)

A control apparatus for a vehicle internal combustion engine in a vehicle having an internal combustion engine and a vehicle drive system,
A target torque setting unit for setting a target torque of the internal combustion engine;
A target torque correction unit that corrects the target torque to a corrected target torque by filter processing;
An output torque adjusting unit using a throttle attached to the internal combustion engine to generate an output torque according to the correction target torque by the internal combustion engine;
On the basis of the throttle opening degree, a throttle model that calculates the throttle passage air quantity, the engine torque model for calculating the intake system model and engine torque from the cylinder intake air amount calculates the cylinder intake air quantity from the throttle air flow A predicted torque calculation unit for calculating the predicted torque using
An air flow meter,
An air flow meter model for calculating the output of the air flow meter based on the output of the throttle model, and a throttle passing air amount correction means for correcting the throttle passing air amount based on the output of the air flow meter and the output of the air flow meter model When,
An internal combustion engine for a vehicle, comprising: an ignition timing adjusting unit that adjusts an ignition timing of the internal combustion engine so as to eliminate the deviation based on a deviation between the corrected target torque and the predicted torque. Control device.   A vehicle inverse model that obtains a required combustion torque from the target torque, an engine inverse model that obtains a required intake air amount from the required combustion torque, an intake system inverse model that obtains a required throttle passage air amount from the required intake air amount, and 2. The control apparatus for an internal combustion engine for a vehicle according to claim 1, wherein the throttle opening is estimated using a throttle inverse model that obtains an estimated throttle opening from a required throttle passing air amount. The control apparatus for an internal combustion engine for a vehicle according to claim 1 or 2 , wherein the throttle passage air amount correction means has a first-order lag element to be applied to the output. 4. The throttle model according to claim 1, wherein the throttle passage air amount correction means updates the throttle model at a predetermined timing based on the output of the air flow meter and the output of the air flow meter model. The control device for an internal combustion engine for a vehicle according to the item .

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