JP5708468B2 - Control device and control method - Google Patents

Description

  The present invention relates to an alternator control device that reduces a generated voltage so that a torque of an alternator decreases with a decrease in vehicle speed.

  In CVT cars and AT cars, the rotation of the engine is transmitted to the transmission by a torque converter, and the torque converter often includes a clutch mechanism for connecting and disconnecting the engine and the transmission. The torque converter with a clutch mechanism suppresses a decrease in transmission efficiency caused by fluid slip in the torque converter by directly connecting the engine and the transmission under predetermined conditions. When the accelerator pedal is no longer depressed, a predetermined ECU (Electronic Control Unit) stops fuel injection and increases the power generation voltage of the alternator. The wheels rotate the engine by keeping the clutch mechanism directly connected to the engine and the transmission, so that it is possible to efficiently generate power without consuming fuel.

  When the vehicle speed or the engine speed decreases, the ECU shifts down because, for example, the vehicle speed falls below a threshold value. By the shift down, a shock (deceleration, acceleration fluctuation, hereinafter referred to as “acceleration / deceleration fluctuation”). ) May occur. This acceleration / deceleration fluctuation occurs because the transmission increases the gear ratio in order to prevent engine stall as the vehicle speed decreases. As the gear ratio increases, the change in vehicle deceleration rapidly increases before the lockup is released.

  Immediately after releasing the lock-up, acceleration / deceleration fluctuation may occur due to a release feeling due to sudden release of the clutch and generation of driving force accompanying the end of fuel cut.

  For this reason, the technique which reduces the acceleration / deceleration fluctuation | variation before and behind lockup is considered conventionally (for example, refer patent document 1). Patent Document 1 discloses a control device that increases an auxiliary load that acts on the internal combustion engine as the fuel cut of the internal combustion engine starts and decreases the auxiliary load as the fuel cut ends.

JP 2010-019129 A

  However, in the control device disclosed in Patent Document 1, the deceleration increases because the auxiliary load is increased at the time of fuel cut, and on the contrary, the acceleration / deceleration fluctuation due to the increase in the gear ratio may be amplified. In addition, the amount of power generation during deceleration is reduced by an amount corresponding to an increase in the auxiliary machine load.

  In view of the above problems, an object of the present invention is to provide a control device for a driving force transmission device that reduces deceleration fluctuations associated with unlocking.

The present invention relates to an alternator control device that reduces the generated voltage so that the torque of the alternator decreases in accordance with a decrease in vehicle speed, and estimates the transmission gear ratio when the torque converter is unlocked. And a target torque of the alternator that becomes smaller as the current speed ratio approaches the speed ratio at the time of releasing the lockup, and a target generated voltage of the alternator is determined using a difference between the target torque and the actual torque of the alternator. Alternator control means, and the alternator control means, before releasing lockup when the vehicle speed is reduced, the alternator target power generation voltage or target torque so that the power generation amount of the alternator does not increase beyond a predetermined value. It is characterized by limiting.

  It is possible to provide a control device for an alternator that reduces fluctuations in deceleration caused by unlocking.

It is an example of the figure explaining suppression of torque fluctuation in control which reduces the torque of an alternator at the time of deceleration. It is an example of a schematic block diagram of a vehicle drive device and ECU which controls this. It is an example of the functional block diagram of ECU. It is an example of the figure explaining the control effect obtained by ideal deceleration and this deceleration. It is an example of the flowchart figure which shows the procedure which estimates the gear ratio at the time of lockup cancellation | release. It is a figure which shows an example of the flowchart figure which shows the control procedure of the alternator torque which makes Jerk constant. It is an example of the flowchart figure which shows the procedure of PI calculation. It is an example of the control block diagram of PI calculation. It is an example of the flowchart figure which shows the procedure of PI calculation in control of the target electric power generation voltage corresponding to the fluctuation | variation of an electrical load. It is an example of the figure explaining the effect by control of target electric power generation voltage. It is a figure which shows an example of the flowchart figure which determines the power generation voltage at the time of deceleration, and an exciting current map.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is an example of a diagram illustrating suppression of alternator torque fluctuations accompanying fluctuations in electrical load in control for reducing alternator torques during deceleration. FIG. 1 shows the alternator target voltage, alternator torque, and electric load on the same time axis.

First, the control for reducing the acceleration / deceleration fluctuation before and after the lockup release and the inconvenience in the control will be described.
(1) First, an ECU (Electronic Control Unit) of the present embodiment gradually reduces the torque of the alternator during deceleration to reduce the acceleration / deceleration fluctuation before and after the lockup is released. Since the torque of the alternator is gradually reduced, the deceleration becomes moderate (for example, Jerk becomes constant), and the acceleration / deceleration fluctuation before and after the lockup is released is reduced.
(2) As a method of reducing the alternator torque, there is a method of feeding back the torque of the alternator to the target generated voltage of the alternator. That is, this is a method of determining a target control torque at which the torque of the alternator gradually decreases and controlling the target power generation voltage of the alternator so as to become the target control torque. As shown in FIGS. 1A and 1B, as the alternator target control torque gradually decreases, the alternator target power generation voltage also gradually decreases.
(3) However, as shown in FIG. 1 (c), the electrical load (the load of the auxiliary machine) may suddenly decrease during the lockup. In this case, since the power generation voltage of the alternator increases as the load decreases, the alternator decreases the power generation amount. As the power generation amount decreases, the actual torque of the alternator also decreases as shown in FIG. Then, a deviation occurs between the target control torque of the alternator and the actual torque, but since this deviation is fed back to the target generated voltage, the target generated voltage of the alternator increases as shown in FIG. End up.
(4) When the target power generation voltage of the alternator increases, the actual torque of the alternator also increases, so the engine load changes. Then, there is a possibility that the lockup release may be affected, for example, the lockup release is not performed at the timing of releasing the lockup, or the lockup is not released at the timing at which the lockup should be released.

Therefore, the ECU of the present embodiment reduces the influence on the lock-up release of (4) as follows.
I. As shown in FIG. 1 (e), even if the actual torque of the alternator falls below the target control torque, the target generated voltage is not increased as shown in FIG. 1 (d).
II. Therefore, even if the electric load suddenly decreases during deceleration in the lockup state, the target generated voltage does not increase, so that the actual torque of the alternator hardly increases as shown in FIG.

  By controlling in this way, when the torque of the alternator is reduced so as to make Jerk constant, the acceleration / deceleration fluctuation before and after the lockup release is suppressed, and the influence on the lockup release can be reduced.

[Configuration example]
FIG. 2 shows an example of a schematic configuration diagram of the vehicle drive device 200 of the present embodiment and the ECU 100 that controls the vehicle drive device 200. One of the output shafts of the engine 12 is connected to the torque converter 13, and the other output shaft is connected to the winding transmission mechanism 17.

  The engine 12 is a known reciprocating engine or diesel engine, and the type of fuel is not limited. In the case of a reciprocating engine, a crankshaft (not shown) is rotated by repeating four steps of intake, compression, expansion, and exhaust. The crankshaft is connected to the torque converter 13. The ECU 100 determines a necessary torque from the map according to, for example, the accelerator opening, the engine rotation speed, and the vehicle speed, and controls the fuel injection amount and the ignition timing.

  The torque converter 13 has a pump impeller and a turbine liner, and transmits the rotation of the engine 12 to the transmission side via fluid (oil). When the pump impeller is rotated by the engine 12, the oil is sent to the turbine liner side. The turbine liner side is also rotated by oil, but the oil that has rotated the turbine liner wraps around the back surface of the pump impeller and rotates the pump impeller. As a result, the pump impeller rotates at a torque larger than the input torque from the engine 12.

  The torque converter 13 includes a lockup clutch mechanism. This lock-up clutch mechanism operates based on hydraulic control by a hydraulic control circuit, and enables direct power transmission between the engine side and the transmission side of the torque converter 13. Note that the transmission side of the torque converter 13 including the lockup clutch mechanism is connected to a rotation direction switching mechanism (not shown) that reverses the direction of rotation input from the engine 12. The rotation direction switching mechanism enables the vehicle to move backward by reversing the direction of rotation input from the engine 12 when the vehicle moves backward.

  The turbine liner side of the torque converter 13 is connected to the transmission 14. The transmission 14 is a CVT (Continuously Variable Transmission: CVT) capable of continuously changing a transmission gear ratio steplessly. Although an automatic transmission that automatically changes to a finite gear ratio may be used, CVT in which the gear ratio continuously changes is suitable for this embodiment. CVT, for example, wraps a metal belt around two pulleys (primary pulley and secondary pulley) on the input side (engine side) and output side (drive shaft side), and changes the diameter of the two pulleys. Change the number and the rotation speed ratio on the wheel side. The CVT structure may be a toroidal CVT that uses rollers and disks instead of belts and pulleys.

  The ECU 100 controls the torque determined from the depression amount of the accelerator pedal or the like to the engine rotation speed and the gear ratio that can be obtained most efficiently, thereby improving the fuel consumption. The output of the transmission 14 is connected to a drive shaft 19 via a reduction gear (not shown), a propeller shaft (in the case of an FR vehicle) 18 and a differential.

A winding transmission mechanism 17 connected to the other output shaft of the engine 12 transmits the rotation of the engine 12 to the auxiliary machine 11 and the alternator 15. The auxiliary machine 11 in the broad sense includes an alternator, but in this embodiment, the auxiliary machine 11 and the alternator are handled separately. The auxiliary machine 11 other than the alternator includes a cooling fan, a water pump, an air conditioner compressor,
The winding transmission mechanism 17 rotates a belt for power generation for operating them in addition to the alternator 15. The electric power generated by the alternator 15 is supplied to various electric loads and the battery 16 with low power consumption.

  The alternator 15 rotates the field coil in an excited state to generate an induced power in the stator coil, converts the induced current into a direct current by a rectifier, and charges the battery 16. The alternator 15 includes a regulator that adjusts the charging voltage. The alternator 15 controls the excitation current flowing in the field coil in accordance with a target voltage set in the regulator from the ECU 100 described later. Thereby, the induced electric power (generated voltage of the alternator) generated in the stator coil is controlled.

  When the excitation current flowing in the field coil increases, the rotational resistance between the stator coil and the alternator torque increases. Therefore, the torque of the alternator 15 increases or decreases the load of the engine 12 by the generated voltage. The relationship between the torque of the alternator 15 and the generated voltage is related by a map or the like. Alternatively, the torque of the alternator 15 may be detected by a torque sensor.

  The ECU 100 is an electronic control device that controls the generated voltage of the alternator 15, the engine 12, and the transmission 14. The ECU 100 includes a microcomputer including a CPU, a RAM, a ROM, an input / output channel, a CAN (Controller Area Network) communication device, and the like. The ROM stores a program for controlling the alternator 15, the engine 12, the transmission 14, and the like. The CPU executes the program and controls various hardware to provide the following functions.

  FIG. 3 is an example of a functional block diagram of the ECU 100. An accelerator pedal sensor 31 and a vehicle speed sensor 32 are connected to the ECU 100. In addition, although various vehicle information can be obtained from CAN communication and a sensor, illustration is abbreviate | omitted. The ECU 100 includes a fuel cut unit 21, a power generation control unit 22, and a lockup control unit 23. The power generation control unit 22 includes a speed ratio estimation unit 24, an alternator torque control unit 25, and a power generation voltage instruction unit 26.

  The fuel cut unit 21 stops fuel supply to the engine 12 on condition that a predetermined condition is satisfied. The predetermined condition is, for example, that the accelerator pedal opening is zero, but it may be added to the predetermined condition that the vehicle speed is a certain value or more. It does not matter whether or not the brake pedal is depressed. Further, even if the driver depresses the accelerator pedal in the vehicle, the fuel supply may be stopped when the speed limiter approaches, for example, the speed limiter. Therefore, the predetermined condition in a broad sense refers to a state where engine driving is no longer necessary.

  Further, the alternator torque control unit 25 calculates a target generated voltage of the alternator 15 during deceleration. The alternator torque control unit 25 determines a target power generation voltage (hereinafter referred to as a deceleration control power generation voltage) when the vehicle speed is not equal to or higher than the threshold value in the locked-up state. This determination of the deceleration control generated voltage corresponds to torque control of the alternator 15 for reducing acceleration / deceleration fluctuations before and after lockup. As will be described in detail later, the alternator torque control unit 25 calculates a target control torque of the alternator 15 and calculates a deceleration control power generation voltage from the target control torque. The gear ratio estimation unit 24 estimates a gear ratio at the time of unlocking in order to calculate a target control torque.

  The generated voltage instruction unit 26 instructs the alternator 15 with the target generated voltage. In this embodiment, there are three types of target power generation voltages. One is a target power generation voltage (hereinafter referred to as a maximum target power generation voltage) when the vehicle speed is equal to or higher than a threshold value when the fuel is cut. The other is a target power generation voltage in a state where the fuel is not cut (hereinafter referred to as a minimum target power generation voltage). The maximum target generated voltage is, for example, 15 [V], and the minimum target generated voltage is, for example, 12.5 to 13.5 [V]. In the latter case, the power generation voltage instruction unit 26 instructs a minimum target power generation voltage that increases as the vehicle speed increases and the battery level decreases, and indicates a minimum target power generation voltage that decreases as the vehicle speed decreases and the battery level increases. The numerical value is merely an example, and the maximum target generated voltage only needs to be higher than the minimum target generated voltage. By increasing the target power generation voltage (maximum target power generation voltage) at the time of fuel cut, the regenerative power by which the wheels turn the engine 12 can be efficiently converted into electricity. The third is a deceleration control power generation voltage for reducing acceleration / deceleration fluctuations before and after lockup determined by the alternator torque control unit 25.

  The power generation control unit 22 limits the change rate of the target power generation voltage so that the target power generation voltage does not suddenly increase or decrease when the target power generation voltage is changed. This is because when the target power generation voltage suddenly increases, the supply voltage to the electrical component suddenly increases and the passenger may feel uncomfortable (for example, the operating speed of the wiper suddenly increases). In addition, if the target power generation voltage suddenly decreases, the supply voltage to the electrical component is not sufficient. Therefore, when the deceleration generated voltage V calculated by the alternator torque control unit 25 is less than the change rate of the target generated voltage, the target generated voltage is limited to the lower limit value of the change rate.

The lockup control unit 23 performs lockup and release independently of power generation control. The lockup control unit 23 has a lockup / lockup release switching map using the throttle opening and the vehicle speed as parameters. For example, in the switching map, a lockup line and a lockup release line are defined in association with the throttle opening and the vehicle speed. The reason why the two lines do not match is to provide hysteresis. The lockup control unit 23 refers to the switching map based on the actual throttle opening and vehicle speed, and controls lockup and release thereof. In the unlocked state, the vehicle is locked up when the set of the vehicle speed and the throttle opening changes beyond the lockup line. Further, in the lockup state, when the vehicle speed and throttle opening pair change beyond the lockup release line, the lockup is released. In a state where the throttle opening is zero (accelerator off), the vehicle speed at which the lockup is released becomes the lowest vehicle speed on the lockup release line, and can be easily obtained.
[Determination of deceleration control generated voltage]
In general, the ideal deceleration is said to be a deceleration with little change in Jerk. Therefore, the alternator torque may be controlled so that the deceleration of the vehicle becomes a deceleration with little change in Jerk. Jerk is equivalent to the first-order time derivative of the deceleration.

  FIG. 4 is an example of a diagram for explaining an ideal deceleration and a control effect obtained by this deceleration. In FIG. 4, the vehicle speed, deceleration, alternator control, and gear ratio γ are displayed on the same time axis. Since the driver has finished depressing the accelerator pedal at time t1, the vehicle starts to decelerate. The torque converter 13 is already locked up. Since the accelerator pedal is turned off (deceleration is started) and the vehicle speed is equal to or higher than the threshold value, the generated voltage instruction unit 26 instructs the alternator 15 about the maximum target generated voltage in order to increase the generation efficiency.

  The gear ratio γ gradually increases from time t1 in order to prevent engine stall. The deceleration of the vehicle increases as the gear ratio increases (deceleration is also caused by engine rotation resistance, alternator torque, etc.). For example, when the vehicle speed becomes smaller than the threshold value after time t2, the deceleration suddenly decreases, and the acceleration / deceleration fluctuation before and after lockup increases (deceleration indicated by a dotted line in the figure).

  Therefore, the alternator torque control unit 25 controls the torque of the alternator 15 so that a deceleration with a small change in Jerk (so that the deceleration becomes substantially constant) is obtained when the vehicle speed becomes smaller than the threshold value. The target deceleration is a deceleration as shown by a solid line, and this deceleration can reduce the change in the deceleration of the vehicle even if the gear ratio is increased before the lockup is released.

In order to obtain a deceleration with little change in the Jerk of the solid line in FIG. 4, the torque of the alternator 15 may be gradually reduced to the gear ratio for releasing the lockup. However, the gear ratio γ at the time of unlocking is not constant because it can change depending on the deceleration of the vehicle. Therefore, the speed ratio γ _end when the lockup is released is estimated using the vehicle speed when the lockup is released.

FIG. 5 is an example of a flowchart showing a procedure for estimating the transmission gear ratio γ _end when the lockup is released. This process is executed as part of the procedure shown in FIG. That is, the vehicle is decelerating with the accelerator off, and the vehicle speed is smaller than the threshold value. Note that the torque converter 13 is already locked up.

  First, the gear ratio estimation unit 24 acquires the current vehicle speed from the vehicle speed sensor 32 (S401).

  Then, acceleration is calculated from the vehicle speed (S402). Since the vehicle is decelerating, the acceleration is negative. The acceleration is obtained, for example, by subjecting the vehicle speed to a time differentiation process (replacing the difference from the previous value with a change in the vehicle speed per unit time).

  Next, the gear ratio estimation unit 24 calculates the vehicle speed when the lockup is released (S403). The vehicle speed when the lockup is released is obtained from the vehicle speed when the throttle opening is zero on the lockup release line. This is corrected by deceleration (the higher the deceleration, the higher the vehicle speed of the release, and the lower the deceleration, the lower the vehicle speed of the release), thereby obtaining the vehicle speed when the lockup is released.

  The gear ratio estimation unit 24 calculates the rotation speed of the primary pulley when the lockup is released using the vehicle speed in S403 (S404). The vehicle speed and the number of revolutions of the primary pulley when the lockup is released are experimentally obtained in advance. That is, if the vehicle speed at the time of unlocking is known, the rotation speed of the primary pulley can be obtained by a map or a function.

  Next, the gear ratio estimation unit 24 calculates the rotation speed of the secondary pulley when the lockup is released using the vehicle speed of S403 (S405). Since the rotation speed of the secondary pulley is decelerated by the reduction mechanism and transmitted to the wheels, it can be uniquely determined from the reduction ratio of the reduction mechanism and the vehicle speed.

As described above, since the rotation speeds of the primary pulley and the secondary pulley have been obtained, the gear ratio estimation unit 24 estimates the gear ratio γ _end when the lockup is released (S406).

Then, the gear ratio estimation unit 24 corrects the gear ratio γ _end estimated in S406 (S407). Since the speed ratio γ has an upper limit and a lower limit, the speed ratio γ is corrected to a value that does not exceed the upper limit, or is corrected to a value that can be taken as an efficient speed ratio designed in advance.

Since the gear ratio γ _end to be unlocked can be estimated, an alternator that becomes smaller from the gear ratio γ _start when the control to make the gear ratio γ _end and Jerk constant is started is reduced according to the current change of the gear ratio γ. calculating the target control torque _{T D} of 15. The following formula is an example of a calculation formula for obtaining the target control torque T _D.

式（１）
Ｔ_０：Ｊｅｒｋ一定制御を開始した時に読み出されたオルタネータのトルク
Ｔ_Ｄ：目標制御トルク
γ_start：Ｊｅｒｋ一定制御を開始した時の変速比
γ_end：ロックアップ解除時の変速比
γ：Ｊｅｒｋ一定制御の制御中に求めた現在の変速比
式（１）では、変速比γ_endと変速比γ_startの差に対する、変速比γ_endと現在の変速比γの差の比に、制御開始時のオルタネータのトルクＴ_０をかけたものとなる。よって、Ｔ_０の係数は最大でも１以下であり、現在の変速比γが変速比γ_endに近づくに従いゼロに近くなる。このため、目標制御トルクＴ_Ｄも徐々にゼロに接近し、この時の目標発電電圧は最小目標発電電圧よりも小さくなる。

Formula (1)
T ₀ : Alternator torque read when Jerk constant control is started T _D : Target control torque γ _start : Gear ratio γ _end when Jerk constant control is started γ _end : Gear ratio γ when lockup is released γ: Jerk constant the current gear ratio formula was determined during the control of the control (1), for the difference in the gear ratio gamma _start and the gear ratio gamma _{end the,} the gear ratio gamma _{end the} a current to the ratio of the difference between the gear ratio gamma, control starting Alternator torque T ₀ is applied. Therefore, the coefficient of T ₀ is at most 1 or less, and approaches zero as the current gear ratio γ approaches the gear ratio γ _end . Therefore, the target control torque T _D also gradually approaches zero, the target generation voltage at this time is smaller than the minimum target generation voltage.

Subsequently, the calculation of the deceleration generated voltage will be described using the target control torque T _D. Alternator torque control unit 25, by feeding back the target control torque T _D to a target generation voltage of the alternator 15 to calculate the target generated voltage to be Jerk constant.

  FIG. 6 shows an example of a flowchart showing an alternator torque control procedure for making Jerk constant, and FIG. 7 shows an example of a flowchart showing a procedure of PI calculation in S60 of FIG. FIG. 8 shows an example of a control block diagram of the PI calculation in S60 of FIG. The procedure of FIG. 6 is started by IG-ON and executed at every cycle time.

  First, the power generation control unit 22 determines whether or not the accelerator is off (S10). Since the accelerator is off, the vehicle may be decelerating.

  When the accelerator is not off (No in S10), the generated voltage instruction unit 26 instructs the alternator 15 to specify the minimum generated voltage (S90).

  When the accelerator is off (Yes in S10), the power generation control unit 22 determines whether or not the vehicle speed is equal to or higher than a threshold value (S20). This is because the acceleration / deceleration fluctuation before and after the lockup is released does not occur when the vehicle speed is equal to or higher than the threshold value. When the vehicle speed is equal to or higher than the threshold (Yes in S20), the generated voltage instruction unit 26 instructs the alternator 15 about the maximum generated voltage (S80).

  When the vehicle speed is not equal to or higher than the threshold (No in S20), the alternator torque control unit 25 starts calculating the deceleration generated power voltage (Jerk constant control). Therefore, the start condition of the Jerk constant control is, for example, that the accelerator is off and the vehicle speed is less than the threshold value.

First, the alternator torque control unit 25 reads the torque T _{0 of the} alternator 15 from a map or the like based on the current generated voltage (S30).

Then, the gear ratio estimation unit 24 calculates the gear ratio γ _end when the lockup is released (S40). The method for obtaining γ _end has been described with reference to FIG.

Next, alternator torque control unit 25, the gear ratio using equation _{(1) γ end, T 0} , γ start, and using the gamma, to calculate the target control torque _{T D} (S50).

  Then, the alternator torque control unit 25 obtains the deceleration generation voltage V by the following equation (2) (S60).

V (n) = V (n-1) + ΔV
= V (n-1) + KP {ΔT (n-1) - (T D -T)} + KI∫ (T D -T) dt ... Equation (2)
KP is a gain in proportional control, and KI is a gain in integral control. Further, V (n−1) is the deceleration generation voltage V one cycle before. Details of the formula which will be described later, is fed back to the difference between the target control torque T _D and alternator torque during deceleration generated voltage by the PI calculation. PID control or the like may be used in addition to PI control.

  Then, the alternator torque control unit 25 sets the deceleration generated voltage V to the alternator 15 (S50). The generated voltage of the alternator 15 gradually decreases, and the torque of the alternator 15 also decreases.

The calculation of the deceleration generated voltage V in step S60 will be described with reference to FIGS.
First, the comparator 41, as shown in FIG. 8, and outputs the difference ΔT of the torque T of the actual alternator 15 detected the target control torque T _D. The torque difference ΔT is output to the integrator 42 and the P control side 48.

  The integrator 42 integrates the torque difference ΔT. The P control side 48 includes a comparator 43, a delay circuit 45, and a multiplier 44. First, the delay circuit 45 holds the torque difference ΔT one cycle before and outputs it to the comparator 43. The comparator 43 calculates the difference ΔT between the current torque difference ΔT and the ΔT one cycle before. Then, the multiplier 44 multiplies the proportional control gain by ΔΔT to perform a proportional calculation. The reason why proportional control is performed not on ΔT but on ΔΔT is that the direct control object is not torque but target generated voltage.

  The adder 46 adds the output of the integrator 42 and the output of the multiplier 44 to calculate ΔV. The adder 47 adds this ΔV and the previous deceleration generation voltage V to calculate the deceleration generation voltage V that is the current target generation voltage.

FIG. 7 is a flowchart of the control block of FIG. First, the alternator torque control unit 25 calculates the difference ΔT = T _D −T between the target alternator torque T read from the target control torque T _D and the difference between the previous ΔT and the current ΔT = ΔΔT = ΔT (n−1) −. ΔT is calculated (S601). The calculation of ΔT corresponds to the processing of the comparator 41, and the calculation of ΔΔT corresponds to the processing of the comparator 43.

Next, ΔV = KP {ΔT (n−1) − (T _D −T)} + KI｝ (T _D −T) dt is calculated (S602). The first term is the calculation on the P control side 48, and the second term is the calculation on the integrator 42.

  The alternator torque control unit 25 adds ΔV in S602 and the previous deceleration power generation voltage V to calculate the current deceleration power generation voltage V (S603). This process corresponds to the addition of the adder 47.

As described above, the deceleration from the target control torque T _D to a Jerk constant, the target generation voltage of the alternator 15 is obtained. Therefore, acceleration / deceleration fluctuations before and after unlocking can be reduced.

[Indication of target generated voltage corresponding to fluctuations in electrical load]
However, since the deceleration generated voltage V obtained by the procedures of FIGS. 6 to 8 allows the deceleration generated voltage V to increase, the torque of the alternator 15 decreases when the electric load fluctuates. There is a risk of increasing the target generated voltage. When the target power generation voltage increases, the alternator torque increases, and acceleration / deceleration fluctuations may occur when lockup is released. Therefore, in this embodiment, the deceleration generation voltage V is determined so that the deceleration generation voltage V does not increase.

  FIG. 9 shows an example of a flowchart showing a calculation procedure of the deceleration generated voltage in S60 of FIG. That is, the overall flow of Jerk constant control is the same as in FIG. 6, but the PI calculation procedure in S60 is different in this embodiment.

  In FIG. 9, the process of S4601 to 603 is the same as that of FIG. 7, but the process of S602-1 is newly added.

  The alternator torque control unit 25 calculates ΔV in step S602, and then controls ΔV to be 0 or less (S602-1). That is, ΔV is limited to 0 or less so that the electric load does not fluctuate and the torque of the alternator 15 decreases to increase the target generated voltage. By doing so, it is possible to prevent the generation voltage during deceleration from suddenly increasing and the torque of the alternator 15 from increasing suddenly.

Note that limiting ΔV to 0 or less means
(i) When ΔV> 0 ΔV ← 0
(ii) When ΔV ≦ 0, it means to keep ΔV.

  Here, limiting ΔV to 0 or less includes limiting ΔV to an extremely small value or less. For example, since ΔV is restricted by the upper limit change speed of the target power generation voltage V, the target power generation voltage V does not change beyond the upper limit change speed. Therefore, ΔV may be a maximum and less than a change amount that satisfies the upper limit change speed of the target power generation voltage V. Specifically, a value other than 0 can be set for ΔV so as to be about 1/10 to 1/2 of the upper limit change rate.

[Effect of limiting ΔV to 0 or less]
FIG. 10 is an example of a diagram illustrating the effect of the control of the target power generation voltage according to the present embodiment. In FIG. 10, the target power generation voltage, alternator torque, electric load, engine speed (and turbine speed), and lock-up / release are shown on the same time axis.

The process of the flowchart of FIG. 6, (1) the target control torque T _D of the alternator 15 is reduced, (2) target generation voltage is gradually lowered. (3) When the electric load is reduced, the alternator 15 reduces the amount of power generation so that the voltage is constant, and (4) the torque of the alternator 15 is also reduced. Therefore, the target control torque T _D, the difference ΔT of the actual torque becomes large.

  If this is left, ΔV will increase according to the processing of step S602, but in this embodiment ΔV is limited to 0 or less, so (5) the target power generation voltage increases and thereby the torque of the alternator 15 increases. I don't have to.

Since target control torque T _D is the gear ratio of the alternator 15 is gradually reduced by increasing the torque of the alternator 15 was lowered by the decrease of the electrical load exceeds the target control torque T _D, [Delta] V is a negative value. Thus, (6) the torque of the alternator 15 resumes tracking of the target control torque T _D.

  Further, since the alternator torque does not increase suddenly, the engine speed does not decrease suddenly, and (7) it decreases gently. Note that the turbine rotation speed slowly decreases compared to the engine rotation speed because the gear ratio changes.

  Thus, even under the Jerk constant control, it is possible to prevent the torque of the alternator 15 from rapidly increasing with respect to the decrease in the electric load. Therefore, the influence on lockup control can also be suppressed.

[Alternator torque control method]
In the above description, the target generated voltage is determined by feedback control with respect to the target control torque of the alternator 15. However, when determining the target generation voltage (exciting current) by a map from the target control torque T _D without using feedback control, it is possible to control to suppress increase of torque.

  Since the torque of the alternator 15 is not fed back to the target generated voltage, the target generated voltage does not increase suddenly due to the decrease in torque when the electric load decreases. However, if the electric load increases while the electric load decreases and the target power generation voltage decreases, the target power generation voltage and torque of the alternator may increase suddenly. For this reason, even when feedback control is not used, control for suppressing an increase in torque is effective.

FIG. 11 is a flow chart for determining the deceleration generated power voltage and an example of an excitation current map. The procedure of FIG. 11 corresponds to S60 of FIG. Already, alternator torque control unit 25, calculates the target control torque T _D according to equation (1). Respect to the target control torque T _D, in performing processing equivalent to the processing for limiting the ΔV to 0 or less, it may be controlled target control torque T _D below the previous value (S611).

And controlling the target control torque T _D below the previous value,
(i) Target control torque T _D > Previous value Target control torque T _D ← Previous value
(ii) remains in the case of the target control torque T _D ≦ previous value target control torque T _D In the same manner as [Delta] V, to controlling the target control torque T _D below the previous value, the previous target control torque T _D Including making the value slightly larger than the value.

Alternator torque control unit 25, in this way on the basis of the target control torque T _D as determined with reference to the exciting current map for determining the excitation current (S442). The exciting current in the exciting current map is an exciting current of the field coil that can obtain a generated voltage equivalent to the target generated voltage obtained by the PI calculation. Exciting current, since the generated voltage is increased larger, depending on the generated voltage, the relationship between the target control torque T _D and the exciting current varies. Further, since the power generation amount of interest is obtained with a small excitation current higher the rotational speed of the alternator in accordance with the alternator speed relationship between the target control torque T _D and the exciting current varies. Therefore, the exciting current map is prepared according to the generated voltage and the alternator rotation speed.

The alternator torque control unit 25 determines an excitation current to be instructed to the alternator 15 with reference to the excitation current map based on the target control torque T _D , the alternator rotation speed, and the current generated voltage. With the excitation current determined in this way, the target generated voltage does not become larger than the previous target generated voltage.

  Thereafter, the generated voltage instruction unit 26 instructs the alternator 15 on the excitation current instead of S70 in FIG. As a result, the alternator 15 can generate power at a power generation voltage equivalent to the target power generation voltage obtained by PI control, so that a constant Jerk deceleration is obtained, and the torque of the alternator 15 increases due to fluctuations in the electrical load. Can be suppressed.

As described above, ECU 100 of the present embodiment, by a method of calculating the Jerk constant alternator torque determined the exciting current from the target control torque T _D, the decrease of the electric load can be suppressed torque of the alternator fluctuates .

11 Auxiliary machine 12 Engine 13 Torque converter 14 Transmission 15 Alternator 16 Battery 100 ECU

Claims (6)

An alternator control device that lowers the generated voltage so that the torque of the alternator decreases as the vehicle speed decreases.
Gear ratio estimating means for estimating a gear ratio of the transmission when unlocking the torque converter;
An alternator control means for determining a target torque of the alternator that becomes smaller as the current speed ratio approaches the speed ratio at the time of releasing the lockup, and for determining a target generated voltage of the alternator using a difference between the target torque and the actual torque of the alternator And having
The alternator control means limits the target power generation voltage or the target torque of the alternator so that the power generation amount of the alternator does not increase beyond a predetermined value before unlocking when the vehicle speed decreases. Control device. The alternator control unit determines the target generation voltage of the alternator by feeding back the difference between the actual torque of the target torque and the alternator to the target generation voltage of the alternator,
Even when the actual torque of the alternator is smaller than the target torque, the target power generation voltage is determined so that the target power generation voltage does not increase beyond a predetermined value.
The control device according to claim 1. The alternator control means, even by the feedback control is necessary to increase the target generated voltage, said not increase the target generation voltage, the control device according to claim 2, wherein a. When the determined target torque is larger than the previous target torque, the alternator control means maintains the determined target torque at the previous target torque,
From the map in which the target torque and the excitation current of the alternator are associated, the excitation current associated with the target torque is read and set in the alternator.
The control device according to claim 1.   The alternator control means determines the target torque so that the deceleration of the vehicle approaches substantially constant when an accelerator-off and lock-up torque converter transmits the wheel rotation to the alternator to generate electric power. The control device according to claim 1. A control method for an alternator control device that reduces the generated voltage so that the torque of the alternator decreases as the vehicle speed decreases.
A gear ratio estimation step for estimating a gear ratio of the transmission at the time of unlocking the torque converter;
An alternator control step of determining a target torque of the alternator that decreases as the current speed ratio approaches the speed ratio at the time of unlocking and determining a target generated voltage of the alternator using a difference between the target torque and the actual torque of the alternator When,
Limiting the target power generation voltage or the target torque of the alternator so that the power generation amount of the alternator does not increase beyond a predetermined value before unlocking when the vehicle speed decreases. .

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