JP2017114252A - Vehicular control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular control apparatus capable of suppressing the deterioration of fuel economy of an internal combustion engine by switching to a lockup state while preventing the generation of muffled noise.SOLUTION: A control apparatus performs: determining, on the basis of engine torque of an internal combustion engine 2 and engine revolution speed thereof, whether muffled noise is generated in the case of switching a lockup clutch 5 from a released state to a lockup state; and decreasing the engine torque so as to prevent generation of the muffled noise and decreasing alternator torque of an alternator 6 as much as the decrease in the engine torque in the case of determining that the muffled noise is generated, thus controlling the lockup clutch 5 to be switchable from the release state to the lockup state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device applied to a vehicle including a torque converter.

  As a vehicle control device, based on the accelerator opening that correlates with engine torque and the vehicle speed that correlates with engine speed, lock-up is implemented to prevent differential rotation of the torque converter at the current accelerator opening and vehicle speed. In this case, it is determined whether or not a booming noise is generated in the case where the noise is generated, and when it is determined that a booming noise is generated, the lockup is not permitted (Patent Document 1).

JP 2008-116053 A

  If lock-up is not performed, the lock-up clutch is released and differential rotation of the torque converter is allowed. That is, a difference in rotational speed occurs between the input side of the torque converter to which the internal combustion engine is connected and the output side of the torque converter to which a power transmission device such as a transmission is connected, so that the fuel consumption of the internal combustion engine may be deteriorated.

  Accordingly, an object of the present invention is to provide a vehicle control device that can suppress deterioration in fuel consumption of an internal combustion engine by switching to a lock-up state while avoiding the generation of a booming noise.

  The vehicle control device of the present invention includes an internal combustion engine, a power transmission device that transmits power of the internal combustion engine to driving wheels, a torque converter provided between the internal combustion engine and the power transmission device, and the torque The present invention is applied to a vehicle including a lockup clutch capable of switching between a release state that allows differential rotation of a converter and a lockup state that restricts differential rotation of the torque converter, and an alternator driven by the internal combustion engine. Determining whether or not a booming noise is generated when the lockup clutch is switched from the released state to the lockup state based on the engine torque and the engine speed of the internal combustion engine, and the booming noise is generated. If it is determined that the engine torque is reduced, the engine torque is reduced so that the generation of the booming noise can be avoided. Amount corresponding to lower the alternator torque of the alternator is the lock-up clutch to control so as to be switched to the lock-up state from the released state.

  According to the control device of the present invention, the engine torque is reduced so as to avoid the generation of a booming noise, and the alternator torque is reduced by the reduction amount so that the lockup clutch can be switched to the lockup state. . For this reason, since it is possible to switch to the lock-up state while avoiding the generation of a booming noise, it is possible to suppress deterioration in fuel consumption of the internal combustion engine. In addition, since the alternator torque is reduced by the reduction in engine torque, the transmission torque transmitted to the power transmission device can be maintained even if the engine torque is reduced.

  In the above and the following, “engine torque” means a torque command value for an internal combustion engine that is not loaded with alternator torque. Therefore, the torque output from the internal combustion engine is obtained by subtracting the alternator torque from the engine torque.

The figure which showed typically the vehicle to which the control apparatus which concerns on one form of this invention was applied. The figure which showed an example of the lockup determination map. The time chart which shows the control content of this form. The time chart which shows the control content of a comparative example. 6 is a flowchart illustrating an example of a control routine according to an embodiment of the present invention.

  As shown in FIG. 1, a vehicle 1 includes an internal combustion engine 2, a step-variable automatic transmission 3 that is a power transmission device for transmitting the power of the internal combustion engine 2 to drive wheels Dw, an internal combustion engine 2, A torque converter 4 provided between the automatic transmission 3, a lockup clutch 5 capable of limiting differential rotation of the torque converter 4, and an alternator 6 driven by the internal combustion engine 2 are provided.

  As an example, the internal combustion engine 2 is configured as a spark ignition type four-cylinder internal combustion engine. The automatic transmission 3 includes an input shaft 3a and an output shaft 3b, and torque transmitted to the output shaft 3b is distributed to the left and right drive wheels Dw via the differential mechanism 10.

  The torque converter 4 includes a pump impeller 11 and a turbine liner 12 that face each other so as to be capable of differential rotation, and a stator 12 provided therebetween. The pump impeller 11 on the input side of the torque converter 4 is connected to the crankshaft 2 a of the internal combustion engine 2, and the turbine liner 12 on the output side is connected to the input shaft 3 a of the automatic transmission 3. The lockup clutch 5 is interposed between the pump impeller 11 and the turbine liner 12. The lock-up clutch 5 releases the pump impeller 11 and the turbine liner 12 to allow the differential rotation of the torque converter 4, and connects the pump impeller 11 and the turbine liner 12 to the differential rotation of the torque converter 4. The lock-up state to be restricted can be switched. The lock-up state includes a complete lock-up state in which the differential rotation is completely prevented and a flex lock-up state in which the differential rotation is slightly allowed.

  The alternator 6 is connected to the crankshaft 2 a of the internal combustion engine 2 through a belt transmission mechanism 15. The belt transmission mechanism 15 includes a driving pulley 16 provided on the crankshaft 2 a, a driven pulley 17 provided on the alternator 6, and a belt 18 wound around these pulleys 16, 17. The belt transmission mechanism 15 is also wound around a pulley (not shown) that drives other auxiliary machines. The alternator 6 is electrically connected to the battery 20, and the generated power of the alternator 6 is supplied to the battery 20.

  The internal combustion engine 2, the automatic transmission 3, the lockup clutch 5, and the alternator 6 are controlled by an electronic control unit (ECU) 30 configured as a computer. The ECU 30 receives output signals from various sensors used for controlling the vehicle 1. For example, the ECU 30 has a crank angle sensor 31 that outputs a signal corresponding to the crank angle of the internal combustion engine 2, a vehicle speed sensor 32 that outputs a signal corresponding to the vehicle speed of the vehicle 1, and a depression amount of an accelerator pedal (not shown). Various output signals such as the accelerator opening sensor 33 that outputs the received signal are input.

  For example, the ECU 30 calculates the required output required for the vehicle 1 with reference to the output signals of the vehicle speed sensor 32 and the accelerator opening sensor 33, and the operating state and automatic shift of the internal combustion engine 2 so that the required output can be achieved. The gear position of the machine 3 is controlled. Further, depending on the operating region of the internal combustion engine 2, when the lockup clutch 5 is switched to the lockup state and the differential rotation of the torque converter 4 is restricted, deterioration of the fuel consumption of the internal combustion engine 2 should be suppressed particularly during acceleration of the vehicle 1. There is.

  Therefore, the ECU 30 uses the lockup determination map shown in FIG. 2, for example, when the vehicle 1 is accelerated to lock up the operating point defined by the engine torque and the engine speed of the internal combustion engine 2 in the lockup determination map. It is determined whether or not it belongs to the region A, and when the operating point belongs to the lockup region A, the lockup clutch 5 is switched from the released state to the lockup state. A flex lockup area a corresponding to the flex lockup state is set in a part of the lockup area A. When the operating point of the internal combustion engine 3 belongs to the flex lockup area a, the ECU 30 activates the lockup clutch 5. Switch to the flex lockup state.

  The lock-up region A is set in consideration of the operation region of the internal combustion engine 2 in which the following booming noise occurs in the lock-up state. Therefore, when the operating point of the internal combustion engine 2 is a low rotation high torque that does not belong to the lock-up region A, the ECU 30 determines that switching to the lock-up state is not permitted because a booming noise is generated when the lock-up state is switched. .

  Due to the output characteristics of the internal combustion engine 2, torque pulsation in which the torque of the crankshaft 2 a periodically fluctuates exists. Therefore, there is a case where a humming noise is generated when the torque pulsation excites vibration of each part of the automatic transmission 3 or the like. is there. A muffled noise is generated in a specific frequency band of torque pulsation, and the magnitude of the muffled noise correlates with the amplitude of torque pulsation. When the lock-up clutch 5 is in the released state, the torque pulsation is attenuated by the torque converter 4, so that the booming noise is less likely to occur. However, when the lock-up clutch 5 is in the lock-up state, the torque pulsation is transmitted to the automatic transmission 3 or the like with a higher transmission sensitivity than in the released state, so it is necessary to take countermeasures against the muffled noise.

  When the operating point of the internal combustion engine 2 belongs to an operation region where a booming noise is generated by switching to the lockup state, that is, when it does not belong to the lockup region A, the ECU 30 changes from the released state of the lockup clutch 5 to the lockup state. It is determined that the switching is not permitted, and the generation of a booming sound accompanying the switching is avoided. The control of the present embodiment is characterized by the control content that is executed when it is determined that switching to the lockup state is not permitted. In this case, the operating point of the internal combustion engine 2 is generated with a muffled sound. It is possible to switch to the lockup state by changing to the low torque side so as to avoid it.

  As shown in FIG. 3A, the ECU 30 determines that the operating point of the internal combustion engine 2 belongs to the lockup area A, here the flex lockup area a, when the accelerator pedal (not shown) is depressed and the accelerator is turned on at time t1. Then, the lockup clutch 5 is switched from the released state to the flex lockup state. At the same time, the ECU 30 controls the internal combustion engine 2 to start increasing the engine torque. When the engine torque exceeds the torque limit Tx, which is the upper limit of the lockup region A, a booming noise is generated.

  As shown in FIG. 3B, in the comparative example in which the control of this embodiment is not performed, when the engine torque reaches the torque limit Tx at time t2, the lockup clutch 5 is switched from the flex lockup state to the release state. On the other hand, the ECU 30 of this embodiment reduces the engine torque when the engine torque reaches the torque limit Tx at time t2, and reduces the alternator torque of the alternator 6 by the amount of decrease in the engine torque. Thereafter, at time t3, when the engine torque is increased again to reach the torque limit Tx, the ECU 30 switches the lockup clutch 6 from the flex lockup state to the released state and starts increasing the alternator torque.

  As is apparent from the comparison of FIG. 3B with the control of this embodiment, the period during which the lock-up clutch 6 is controlled to the lock-up state (flex lock-up state) under the same acceleration condition is from time t2 to time t3. Considerably longer. Further, since the alternator torque is reduced by an amount corresponding to the reduction of the engine torque that is the torque command value of the internal combustion engine 2, even if the engine torque is reduced, the torque of the crankshaft 2a does not change and is transmitted to the automatic transmission 3. Can be maintained.

  The control described above can be realized, for example, by the ECU 30 executing the control routine of FIG. The program of the control routine of FIG. 4 is held in the ECU 30, and is read out in a timely manner and repeatedly executed at predetermined intervals.

  In step S1, ECU30 acquires the vehicle state of the vehicle 1 required by the following processes based on the output signal of various sensors 31-33, or based on the parameter calculated from these output signals. For example, vehicle information such as the current vehicle speed, accelerator opening, engine speed [rpm] and engine torque [Nm] of the internal combustion engine 2, alternator torque [Nm] and alternator power generation voltage [V] of the alternator 6, etc. Get as. In the above and the following description, it is assumed that the alternator torque takes into account the speed ratio of the belt transmission mechanism 15 that connects the alternator 6 and the crankshaft 2a so that torque can be transmitted.

  In step S2, the ECU 30 determines whether or not the vehicle 1 is accelerating, that is, whether or not the accelerator is ON, based on the vehicle state of the vehicle 1 acquired in step S1. In the present embodiment, when the vehicle 1 is not accelerating, the subsequent processing is not performed. When the vehicle is not on, the subsequent processing is skipped and the current routine is terminated. If the accelerator is ON, the process proceeds to step S3.

  In step S3, the ECU 30 determines whether or not the current state of the lockup clutch 5 is in the released state and switching to the lockup state is not permitted. The cases where the switching is not permitted include cases where the operating point of the internal combustion engine 2 does not belong to the above-described lockup region A (FIG. 2), or cases other than the operating point of the internal combustion engine 2. There are cases for reasons.

  In step S4, the ECU 30 determines whether or not the reason for disapproval of switching from the released state to the lockup state is due to the operating point of the internal combustion engine 2 described above, that is, to avoid the generation of a booming noise. To do. If the reason is the operating point of the internal combustion engine 2, the process proceeds to step S5. If not, the subsequent process is skipped and the current routine is terminated.

  In step S5, the ECU 30 determines whether or not the reason for disapproval is eliminated by performing torque reduction control that reduces the engine torque of the internal combustion engine 2 and decreases the alternator torque of the alternator 6. In other words, it is predicted whether or not the operating point after the reduction belongs to the lock-up region A due to the reduction of the engine torque. In the torque reduction control, the alternator torque is reduced by the reduction amount of the engine torque. Therefore, the engine torque can be reduced only by the maximum reduction amount of the alternator torque, that is, the reduction amount that makes the current alternator torque zero.

  Therefore, when assuming that the current engine torque is Te and the current alternator torque is To, the ECU 30 satisfies the following expression 1 between these torques Te and To and the upper limit value of the lockup region A, that is, the torque limit Tx described above. It is determined whether or not the reason for disapproval is resolved depending on whether or not the relationship is established. If the relationship of Formula 1 is established, the ECU 30 advances the process to Step S6. If the relationship of Formula 1 is not established, the ECU 30 has no allowance for reducing the alternator torque and cannot execute the torque reduction control. End the routine.

    Tx> Te-To ...... 1

  In step S6, the ECU 30 calculates an alternator target torque Tot of the alternator 6 that is a target during torque reduction control based on the following equation 2.

    Tot = Te−Tx 2

  In step S7, the ECU 30 calculates a target engine torque Tet of the internal combustion engine 2 that is a target at the time of torque reduction control based on the following equation 3.

    Tet = Te- (To-Tot) ...... 3

  In step S8, the ECU 30 executes the following processes (1) to (3) to calculate the alternator power generation instruction voltage Vot [V] based on the alternator target torque Tot and the current alternator torque To.

(1) A difference Δ [Nm] between the alternator target torque Tot and the current alternator torque To is calculated. That is, Δ = Tot−To is calculated.
(2) In order to convert the calculation result of (1) above into a voltage unit system, the indicated voltage change to the alternator 6 is multiplied by the above difference Δ by a gain K [V / Nm] for conversion into the voltage unit system. The amount ΔV [V] is calculated. That is, ΔV = Δ × K is calculated.
(3) The alternator power generation instruction voltage Vot is calculated by adding the calculation result of (2) to the current alternator power generation voltage Vo. That is, Vot = Vo + ΔV is calculated.

  By repeating these processes (1) to (3), when there is a relationship of Tot> To, the alternator power generation instruction voltage Vot is set to gradually increase as the difference Δ from the target increases. Conversely, when the relationship of Tot <To, the alternator power generation instruction voltage Vot is set gradually smaller.

  In step S9, the ECU 30 instructs the internal combustion engine 2 on the target engine torque Tet on the basis of the calculation results in steps S6 to S8, and instructs the alternator 6 on the alternator target torque Tot. Then, the torque reduction control is performed to reduce the alternator torque of the alternator 6 by that amount, and the current routine is terminated.

  When the control routine of FIG. 4 is executed, when the switching to the lock-up state is not permitted due to the operating point of the internal combustion engine 2, the torque reduction control is performed and the operating point of the internal combustion engine 2 is locked up. It belongs to the area A. For this reason, the lockup clutch 6 can be switched from the released state to the lockup state while avoiding the generation of a booming noise. In addition, the transmission torque transmitted to the automatic transmission 3 side is maintained even when the torque reduction control is performed. Therefore, since the range that can be switched to the lockup state is expanded while maintaining the transmission torque, the performance of both the fuel consumption of the vehicle 1 and the feeling of the driver can be improved.

  This invention is not limited to the said form, It can implement with a various form within the range of the summary of this invention. The lock-up clutch in the above form can be switched to the complete lock-up state or the flex lock-up state as the lock-up state, but the present invention is changed to a lock-up clutch in a form that does not implement the flex lock-up state. It is also possible to implement.

  Although the internal combustion engine of the said form is a spark ignition type internal combustion engine, when implementing this invention, there is no restriction | limiting in particular in the kind of internal combustion engine. For example, the present invention can be applied to a vehicle equipped with a diesel-type internal combustion engine.

  The above-described embodiment includes a step-variable automatic transmission (AT) as a power transmission device, but the configuration of the power transmission device is a vehicle provided with a torque converter between the internal combustion engine and the power transmission device. There is no limit. For example, a continuously variable automatic transmission (CVT) may be used as the power transmission device. Further, the present invention can be applied to a hybrid vehicle in which a so-called hybrid transaxle constituting an electric continuously variable transmission by providing an electric motor is provided as a power transmission device.

  In the above embodiment, torque reduction control is performed during acceleration of the vehicle, but it is possible to change the torque reduction control so that it is performed in cases other than during acceleration.

1 Vehicle 2 Internal combustion engine 3 Automatic transmission (power transmission device)
4 Torque converter 5 Lock-up clutch 6 Alternator 30 ECU

Claims (1)

An internal combustion engine, a power transmission device that transmits power of the internal combustion engine to drive wheels, a torque converter provided between the internal combustion engine and the power transmission device, and a release state that allows differential rotation of the torque converter And a lockup clutch capable of switching between a lockup state for limiting the differential rotation of the torque converter, and an alternator driven by the internal combustion engine.
When the lockup clutch is switched from the released state to the lockup state, it is determined based on the engine torque and the engine speed of the internal combustion engine whether or not a booming noise is generated. When the determination is made, the engine torque is reduced so that the generation of the booming noise can be avoided, and the alternator torque of the alternator is reduced by an amount corresponding to the reduction of the engine torque, so that the lockup clutch is released from the released state to the lockup state. A control device for a vehicle that is controlled so as to be switchable.

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