JP2008157190A - Control device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve torque reduction precision, and restrict torque level difference. <P>SOLUTION: For upshifting speed change (S13), in a case of exhaust temperature below a preset prescribed value (S14), a suction air quantity estimation torque value is determined based on suction air quantity, and a torque reduction ratio (first torque reduction ratio) is determined using a torque correction value determined in accordance with the suction air quantity estimation torque value and speed change ration variation (S15). Engine torque is controlled using ignition timing retard quantity based on the torque reduction ratio (first torque reduction ratio). Since the ignition timing retard quantity is thus determined using the suction air quantity estimation torque value that is close to actual torque, torque reduction precision by retard of the ignition timing is improved to restrict torque shock due to torque level difference, while robustness is greatly improved. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine control device, and more particularly, to an engine control device that reduces engine torque based on an actual intake air amount when shifting a transmission.

Patent Document 1 discloses a control device that controls engine torque at the time of shifting of an automatic transmission by throttle opening control and ignition timing control. That is, the throttle opening degree control in the Patent Document 1, the throttle opening degree so that the deviation is eliminated and the required torque T _t and assuming torque T _e is feedback-controlled. In the ignition timing control in Patent Document 1, the ignition timing is feedback-controlled according to the deviation between the required torque T _t and the engine torque T _q .

Here, the required torque T _t is calculated from a map or the like in accordance with the operation state, gear position, elapsed time, etc. at that time, and the assumed torque _Te is determined in advance with the air charging efficiency C _e , the engine speed, and the like. The engine torque T _q is calculated from the set ignition timing I _G determined according to the operating state from the ignition timing map, and the engine filling rate C _e1 and the engine speed N _e1 after the throttle opening control and the present time It is calculated from the ignition timing _IG1 . The air charging efficiency C _e are those calculated from the engine speed and the intake air quantity.
JP-A-5-163996

In such Patent Document 1, control of the throttle opening degree is feedback-controlled at the time of the automatic transmission shifting, since the required torque T _t and assuming torque T _e match, ignition timing control following the throttle opening control Thus, the retard amount of the ignition timing can be calculated with high accuracy.

However, in such Patent Document 1, it will be a torque step to reduce the steady-state deviation of the assumed torque T _e and the required torque T _t at the start / end of the feedback control of the throttle opening degree occurs, uncomfortable feeling to the driver There is a risk of giving.

  Therefore, the present invention provides an engine control device having a torque adjusting means for controlling engine torque, and an intake air amount detecting means for detecting an intake air amount, and an intake air that is an estimated torque of the engine based on the intake air amount. Intake air amount estimated torque value calculating means for calculating an amount estimated torque value, torque correction value calculating means for calculating a torque correction value in accordance with a change in gear ratio of the transmission, the intake air amount estimated torque value, and the torque correction A torque down rate calculating means for calculating a torque down rate using the value, and an ignition timing correction amount calculating means for calculating an ignition timing retard amount from the torque down rate, wherein the torque adjusting means includes the transmission Shift timing ignition timing correction control for reducing the engine torque using the ignition timing retard amount with respect to the current engine torque at the time of shifting It is characterized by performing. That is, the ignition timing retard amount is calculated using the estimated intake air amount torque value close to the actual torque of the engine calculated based on the intake air amount at the time of shifting of the transmission.

  According to the present invention, since the ignition timing retard amount used when performing the shift timing fire timing correction control is calculated using the estimated intake air amount estimated torque value close to the actual torque, the torque reduction due to the ignition timing retard. Accuracy is improved, torque shock due to torque steps is suppressed, and robustness is greatly improved.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory diagram schematically showing a system configuration of an engine control apparatus according to the present invention.

  An engine 1 on which a vehicle (not shown) is mounted is controlled by an engine control unit (hereinafter referred to as ECU) 2 so as to obtain an optimum engine torque in accordance with the driving state of the vehicle.

  An automatic transmission 4 is connected to a crankshaft 3 that serves as an output shaft of the engine 1. The automatic transmission 4 includes a torque converter 5 having a lock-up mechanism to which driving force is transmitted from the crankshaft 3, and a belt-driven CVT (continuous continuously variable transmission) connected to the engine 1 through the torque converter 5. 6). The output side of the CVT 6 is connected to the drive wheels 8 via the final reduction gear 7 in the same manner as a general automobile. A stepped automatic transmission may be used instead of CVT6.

  In the intake passage 9 connected to the engine 1, a throttle valve 10 that is controlled to be opened and closed by the ECU 2 is disposed, and an air flow meter 11 is disposed downstream of the throttle valve 10 (on the engine 1 side). Yes. An exhaust temperature sensor 13 for detecting the exhaust temperature is disposed in the exhaust passage 12 connected to the engine.

  In addition to the exhaust temperature sensor 13 and the air flow meter 11 described above, the ECU 2 is operated by an engine speed sensor 14 that detects the engine speed, a vehicle speed sensor 15 that detects the speed of the vehicle on which the engine 1 is mounted, and a driver. A signal is input from an accelerator sensor 16 that detects an accelerator operation amount that is an operation amount (depression amount) of an accelerator pedal. Actually, corresponding information is input to the ECU 2 from a number of sensors other than the above-described sensors.

  The automatic transmission 4 is controlled by an automatic transmission control unit 17. The automatic transmission control unit 17 includes a CVT input side rotational speed sensor 18 that detects the input rotational speed of the CVT 6, a CVT output side rotational speed sensor 19 that detects the output rotational speed of the CVT 6, the vehicle speed sensor 15 described above, and the like. The signal from is input. Further, the automatic transmission control unit 17 is connected via a communication line so that bidirectional communication with the ECU 2 is possible. In other words, the ECU 2 receives various signals such as a lock-up signal and a lock-up release signal, the target gear ratio of the CVT 6, and whether the CVT 6 is shifting, via the automatic transmission control unit 17. Information about the state is entered.

  The lockup signal is input to the ECU 2 when a lockup clutch (not shown) of the torque converter 5 is engaged and the engine 1 and the CVT 6 are in a lockup state. The lockup release signal is input to the ECU 2 when the lockup clutch is released and the lockup state is released.

  The ECU 2 normally controls the engine torque by a combination of throttle control for controlling the opening of the throttle valve 10 in accordance with the accelerator operation amount and normal point fire timing control for controlling the ignition timing in accordance with the operating state.

In a scene where the automatic transmission 4 is shifting due to an upshift, the engine timing is reduced by performing a shift timing ignition timing correction control that retards the ignition timing, and a torque shock due to a change in the gear ratio (upshift). Suppress. It should be noted that the shift timing ignition timing correction control is not executed even if the automatic transmission 4 is in a state of shifting due to an upshift unless a predetermined specific condition is satisfied. In the present embodiment, as the specific condition, when the exhaust gas temperature detected by the exhaust gas temperature sensor 13 is equal to or lower than a predetermined value, execution of the shift point ignition timing correction control is permitted. This is because the exhaust gas temperature is already high and the ignition timing is retarded to further increase the exhaust gas temperature, thereby preventing the exhaust purification catalyst (not shown) disposed on the exhaust passage 12 from being excessively heated. To do,
The above-described shift point ignition timing correction control will be described with reference to FIG. The shift timing fire timing correction control is performed during the upshift of the automatic transmission 4 (period in which the rotation synchronization signal is ON in FIG. 2). During the upshift of the automatic transmission 4 (rotation synchronization signal ON), the torque correction value is calculated in the ECU 2 in accordance with the change in the gear ratio due to the upshift of the automatic transmission 4. Then, a torque down rate is calculated using the torque correction value and an intake air amount estimated torque value (indicated by a dotted line in FIG. 2) calculated based on the intake air amount, and ignition is performed from the torque down rate. Calculate the amount of time retard.

  The torque correction value is used to correct the intake air amount estimated torque value in a decreasing direction. If the intake air amount estimated torque value is a positive value, the torque correction value is obtained as a negative value. It is.

  The torque down rate (first torque down rate) calculated using the intake air amount estimated torque value is the intake air amount estimated torque value, the torque correction value, and the torque converted value of the friction of the engine 1. This is a value obtained by dividing the sum of the torque converted value of the auxiliary machine load by the intake air amount estimated combustion torque value. The intake air amount estimated combustion torque value is the sum of the intake air amount estimated torque value, the friction torque converted value of the engine 1 and the torque converted value of the auxiliary load, and the torque correction value is In the case of zero, the torque down rate is 1 (100%). That is, the torque-down rate indicates how much the engine torque is desired to be reduced from the current value. For example, the torque-down rate when the torque is reduced by 5% is 0.95 (95%).

  Then, the ignition timing is retarded from the reference ignition timing in accordance with the torque down rate. Specifically, as shown in FIG. 3, an ignition timing for realizing a desired torque down rate is calculated using a characteristic diagram showing a correlation between the ignition timing and the torque down rate. In other words, the ignition timing retard amount from the reference ignition timing is calculated in order to realize a desired torque reduction rate. Here, the reference ignition timing is a maximum torque ignition timing obtained from an experiment, and is an optimal ignition timing at which the combustion torque is maximum.

  Here, a driver estimated torque value (indicated by a one-dot chain line in FIG. 2) calculated based on the driver's accelerator operation (the opening command value of the throttle valve 10) and the intake air amount estimated torque value In the meantime, as shown in FIG. 2, there are steady deviations caused by temperature, altitude, deviations in the overall performance of the engine due to design changes during development, and the like. That is, the driver estimated torque value includes the steady-state deviation. Therefore, if the driver estimated torque value and the torque correction value are used when calculating the torque down rate, the steady deviation is included as shown in FIG. 2, and extra torque reduction is performed. It will be.

  Note that the torque down rate (second torque down rate) calculated using the driver estimated torque value includes the driver estimated torque value, the torque correction value, the friction torque conversion value of the engine 1, and the auxiliary load. This is a value obtained by dividing the sum of the torque converted value by the driver estimated combustion torque value. Here, the driver estimated combustion torque value is the sum of the driver estimated torque value, the torque converted value of the friction of the engine 1, and the torque converted value of the auxiliary load.

  On the other hand, in the above-described shift timing ignition timing correction control in the present embodiment, the ignition timing retard amount is calculated using the intake air amount estimated torque value close to the actual torque of the engine calculated based on the intake air amount. Therefore, the accuracy of torque reduction due to the ignition timing retard can be improved, the torque shock due to the torque step can be suppressed, and the robustness can be greatly improved.

  The torque adjusting means, intake air amount estimated torque value calculating means, torque correction value calculating means, torque down rate calculating means, and ignition timing correction amount calculating means are included in the ECU 2 described above.

  FIG. 4 shows a control flow of the engine torque at the time of shifting that is repeatedly executed by the ECU 2 at predetermined intervals.

  In step (hereinafter referred to as “S”) 11, it is determined whether or not the automatic transmission 4 is shifting. If shifting is in progress, the process proceeds to S 12. If not shifting, the current routine is terminated. Whether or not the automatic transmission 4 is shifting is detected by the automatic transmission control unit 17.

  In S12, a torque correction value is calculated according to a change in the gear ratio of the automatic transmission 4.

  In S13, it is determined whether or not the shift of the automatic transmission 4 is an upshift. If the shift is an upshift, the process proceeds to S14. If not, the process proceeds to S17.

  In S14, it is determined whether the exhaust temperature detected by the exhaust temperature sensor 13 is equal to or lower than a predetermined value set in advance. If the exhaust temperature detected by the exhaust temperature sensor 13 is equal to or lower than the predetermined value, the ignition timing is determined. Even if the exhaust gas temperature increases due to the retard, it is determined that the exhaust gas purification catalyst is not likely to be heated excessively, and the process proceeds to S15. If the exhaust gas temperature detected by the exhaust gas temperature sensor 13 is not less than the predetermined value, the ignition When the exhaust temperature rises due to the timing retard, it is determined that the exhaust purification catalyst may be excessively heated, and the process proceeds to S17.

  In S15, an estimated intake air amount torque value is calculated on the basis of the intake air amount detected by the air flow meter 11, and a torque reduction rate (using the estimated intake air amount torque value and the torque correction value calculated in S12) is calculated. First torque reduction rate) is calculated, and the process proceeds to S16.

  In S16, the engine torque is controlled using the ignition timing retard amount based on the torque down rate (first torque down rate) calculated in S15. That is, the engine torque is controlled by the shift timing fire timing correction control.

  On the other hand, in S17, the opening command value of the throttle valve 10 is calculated from the driver's accelerator operation, the driver estimated torque value calculated based on the opening command value of the throttle valve 10, and the calculation in S12. A torque down rate (second torque down rate) is calculated using the torque correction value, and the process proceeds to S18.

  In S18, the engine torque is adjusted by using both the throttle control based on the opening command value of the throttle valve 10 calculated in S17 and the ignition timing control based on the torque down rate (second torque down rate) calculated in S17. Control. That is, the engine torque is controlled by a combination of throttle control for controlling the opening degree of the throttle valve 10 according to the accelerator operation amount and normal-time fire timing control for controlling the ignition timing according to the operating state.

  Further, the specific condition for permitting the execution of the shift timing ignition timing correction control is not limited to the exhaust temperature condition described above. For example, whether or not the torque converter 5 is locked up, and the vehicle speed is a predetermined value or less. It is also possible to add conditions such as whether or not the speed change type of the automatic transmission 4 is a predetermined speed change type.

  That is, as shown in FIG. 5, the engine torque during shifting may be controlled.

  In step 21, it is determined whether or not the automatic transmission 4 is shifting. If shifting is in progress, the process proceeds to S22. If not shifting, the current routine is terminated. Whether or not the automatic transmission 4 is shifting is detected by the automatic transmission control unit 17.

  In S22, a torque correction value is calculated according to a change in the gear ratio of the automatic transmission 4.

  In S23, it is determined whether or not the shift of the automatic transmission 4 is an upshift. If the shift is an upshift, the process proceeds to S24. If not, the process proceeds to S30.

  In S24, it is determined whether or not the torque converter 5 is locked up. If the lockup is in progress, the process proceeds to S25, and if not in the lockup, the process proceeds to S30. Since the pump impeller (not shown) and the turbine runner (not shown) are directly connected during lock-up, the torque shock increases unless the engine torque is accurately controlled. This is a condition for performing the shift timing fire timing correction control.

  In S25, it is determined whether or not the vehicle speed detected by the vehicle speed sensor 15 is equal to or lower than a predetermined value. If the vehicle speed is equal to or lower than the predetermined value, the process proceeds to S26, and if not, the process proceeds to S30.

  Since the torque shock is more likely to occur when the vehicle speed is low, the shift timing ignition timing correction control is performed when the vehicle speed is low. In addition, as a predetermined value of the vehicle speed in S26, the value of about 30-40 km / h is set, for example.

  In S26, if the shift in the automatic transmission 4 is a predetermined shift type, for example, 1st to 2nd, or 1st to 3rd, the process proceeds to S27, and if not, the process proceeds to S30. In the case of an upshift on the low-speed gear side, torque shock is likely to occur, so that the shift timing fire timing correction control is performed.

  In S28, it is determined whether or not the exhaust temperature detected by the exhaust temperature sensor 13 is equal to or lower than a predetermined value set in advance. If the exhaust temperature detected by the exhaust temperature sensor 13 is equal to or lower than a predetermined value, the ignition timing is determined. Even if the exhaust gas temperature increases due to the retard, it is determined that the exhaust gas purification catalyst is not likely to be heated excessively, and the process proceeds to S28. If the exhaust gas temperature detected by the exhaust gas temperature sensor 13 is not less than the predetermined value, ignition is performed. When the exhaust temperature rises due to the timing retard, it is determined that the exhaust purification catalyst may be excessively heated, and the process proceeds to S30.

  S28 calculates an intake air amount estimated torque value based on the intake air amount detected by the air flow meter 11, and uses this intake air amount estimated torque value and the torque correction value calculated in S22 to reduce the torque reduction rate ( First torque reduction rate) is calculated, and the process proceeds to S29.

  In S29, the engine torque is controlled using the ignition timing retard amount based on the torque down rate (first torque down rate) calculated in S28. That is, the engine torque is controlled by the shift timing fire timing correction control.

  On the other hand, in S30, the opening command value of the throttle valve 10 is calculated from the driver's accelerator operation, and the driver estimated torque value calculated based on the opening command value of the throttle valve 10 is calculated in S22. A torque down rate (second torque down rate) is calculated using the torque correction value, and the process proceeds to S31.

  In S31, the engine torque is adjusted by using both the throttle control based on the opening command value of the throttle valve 10 calculated in S30 and the ignition timing control based on the torque down rate (second torque down rate) calculated in S30. Control. That is, the engine torque is controlled by a combination of throttle control for controlling the opening degree of the throttle valve 10 according to the accelerator operation amount and normal-time fire timing control for controlling the ignition timing according to the operating state.

  The technical idea of the present invention that can be grasped from the above embodiment will be listed together with the effects thereof.

  (1) In an engine control apparatus having torque adjusting means for controlling engine torque, intake air amount detection means for detecting intake air amount, and intake air amount estimated torque that is an estimated torque of the engine based on the intake air amount An intake air amount estimated torque value calculating means for calculating a value, a torque correction value calculating means for calculating a torque correction value according to a change in the transmission gear ratio, the intake air amount estimated torque value and the torque correction value. A torque-down rate calculating means for calculating a torque-down rate, and an ignition timing correction amount calculating means for calculating an ignition timing retard amount from the torque-down rate. Then, the shift timing fire timing correction control is performed to reduce the engine torque by using the ignition timing retard amount with respect to the current engine torque. That is, the ignition timing retard amount is calculated using the estimated intake air amount torque value close to the actual torque of the engine calculated based on the intake air amount at the time of shifting of the transmission. As a result, the ignition timing retard amount used when performing the shift timing fire timing correction control is calculated using the estimated intake air amount torque value close to the actual torque, so the accuracy of torque reduction due to the ignition timing retard is improved. The torque shock due to the torque step is suppressed and the robustness is greatly improved.

  (2) Specifically, the engine control device according to (1) described above has exhaust temperature detecting means for detecting the exhaust temperature of the engine, and the torque adjusting means is configured such that the transmission is upshifted. When the shift is being performed and the exhaust temperature of the engine is equal to or lower than a predetermined value, the shift timing ignition timing correction control is performed.

  (3) In the engine control device according to (2), specifically, the engine is mounted on a vehicle as a drive source, and the transmission is an automatic transmission having a lock-up mechanism. And a lockup mechanism state determination unit that determines whether or not the lockup mechanism is in a lockup state, and a vehicle speed detection unit that detects a vehicle speed of a vehicle on which the engine is mounted, and the transmission is locked When the vehicle speed of the vehicle is below a predetermined value and the change of the transmission gear ratio is changed from a predetermined transmission gear ratio to a predetermined transmission gear ratio, the shift point ignition timing correction control is performed.

  (4) The engine control device according to any one of (1) to (3), specifically, includes throttle opening detection means for detecting the throttle opening of the engine, and the torque adjustment means. Is a combination of throttle control for controlling the throttle opening in accordance with the amount of accelerator operation and normal ignition timing control for controlling the ignition timing in accordance with the operating state when the transmission is not being shifted. To control the engine torque.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which showed typically the system configuration | structure of the engine control apparatus which concerns on this invention. The timing chart which shows the control operation at the time of the shift of the control apparatus of the engine which concerns on this invention. The characteristic diagram which shows the correlation of ignition timing and a torque down rate. The flowchart which shows the flow of control of the engine torque at the time of shifting of the control apparatus of the engine which concerns on this invention. The flowchart which shows the flow of control of the engine torque at the time of shifting in other embodiment of the control apparatus of the engine which concerns on this invention.

Explanation of symbols

1. Engine 2. Engine control unit (ECU)
4 ... Automatic transmission 5 ... Torque converter 6 ... CVT
17 ... Automatic transmission control unit

Claims (4)

In an engine control device having torque adjusting means for controlling engine torque,
An intake air amount detection means for detecting an intake air amount;
Intake air amount estimated torque value calculating means for calculating an intake air amount estimated torque value that is an estimated torque of the engine based on the intake air amount;
Torque correction value calculating means for calculating a torque correction value according to a change in the transmission gear ratio;
Torque down rate calculating means for calculating a torque down rate using the intake air amount estimated torque value and the torque correction value;
Ignition timing correction amount calculating means for calculating an ignition timing retard amount from the torque reduction rate, and
The engine is characterized in that the torque adjusting means performs shift timing ignition timing correction control for reducing the engine torque by using the ignition timing retard amount with respect to the current engine torque at the time of shifting of the transmission. Control device. Exhaust temperature detecting means for detecting the exhaust temperature of the engine,
The said torque adjustment means performs said shift time-of-fire timing correction control when the said transmission is shifting by an upshift and the exhaust temperature of the engine is below a predetermined value. Engine control device. The engine is mounted on a vehicle as a drive source, and the transmission is an automatic transmission having a lock-up mechanism,
Lockup mechanism state determining means for determining whether or not the lockup mechanism is in a lockup state;
Vehicle speed detecting means for detecting the vehicle speed of a vehicle on which the engine is mounted, the transmission is locked up, the vehicle speed of the vehicle is less than a predetermined value, and a change in the transmission gear ratio is predetermined. 3. The engine control apparatus according to claim 2, wherein the shift timing ignition timing correction control is performed when the gear ratio is changed from a predetermined gear ratio to a predetermined gear ratio. Throttle opening detection means for detecting the throttle opening of the engine,
The torque adjusting means includes a throttle control for controlling the throttle opening in accordance with an accelerator operation amount in a state in which a shift of the transmission is not performed, and a normal timing fire timing for controlling an ignition timing in accordance with an operating state. The engine control apparatus according to any one of claims 1 to 3, wherein the engine torque is controlled in combination with the control.

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