JP2019048592A - Vehicle control device - Google Patents

Abstract

To reduce a concern such that instantaneous interruption occurs in an output voltage of a battery at the time of engine start.SOLUTION: A vehicle 10 includes a power source unit 38 for supplying power to electric/electronic equipment based on an output voltage of a battery 26, and an alternator 24 for charging the battery 26 by gradual excitation power generation, in addition to an engine 12. When the engine 12 starts by establishment of an idle start condition, an ECU 36 executes processing of changing setting of the power source unit 38 so that a load of the electric/electronic equipment is reduced and/or processing of changing setting of the alternator 24 so that a target voltage value in gradual excitation power generation rises in a different form according to a degradation state of the battery 26. When such setting change processing completes, the ECU 36 starts the power source unit 38.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle control apparatus, and more particularly to a vehicle control apparatus that controls a vehicle including a power supply unit that supplies electric power to an electric load based on an output voltage of the battery and an alternator that charges the battery by gradual generation. .

  Since a large current is instantaneously supplied to the starter motor at the time of engine start, when the power supply capacity of the battery is not sufficient, there is a possibility that a system shutdown may occur due to a momentary loss of battery output voltage. Based on this, according to Patent Document 1, when it is determined that a momentary disconnection may occur in the output voltage of the battery in the near future, a supply stop signal for stopping supply of drive power is output to the power supply unit for in-vehicle devices. . The supply of drive power to the in-vehicle device group is stopped by the in-vehicle device power supply unit before the instantaneous interruption occurs.

  The load of the battery is reduced by an amount corresponding to the drive power consumed by the in-vehicle devices, and the minimum voltage of the battery is increased when a large current is supplied to the starter motor. A system failure due to a momentary interruption is avoided by raising the minimum voltage of the battery.

JP, 2014-169013, A

  In Patent Document 1, it is compared with the threshold voltage the battery output voltage whether the battery output voltage may be interrupted in the near future, or the decrease rate per unit time of the battery output voltage is calculated. It is judged by doing.

  However, in such a method, it takes time until power supply to the in-vehicle device group is stopped after it is determined that the battery output voltage may be momentarily interrupted, and as a result, the battery output voltage is momentarily interrupted. It may occur.

  Therefore, a main object of the present invention is to provide a vehicle control device capable of reducing the concern that the output voltage of the battery may be interrupted when the engine is started.

  The vehicle control device according to the present invention is a vehicle control device that controls a vehicle including a power supply unit that supplies electric power to an electric load based on an output voltage of a battery, and an alternator that charges the battery by gradual generation. The process of changing the setting of the power supply unit so that the electric load is reduced when the engine is started and / or the process of changing the setting of the alternator so that the target voltage in the gradual generation increases. And a start-up means for starting the power supply unit after the process of the setting change means.

  When the engine is started, the setting of the power supply unit is adjusted to reduce the electrical load, or the setting of the alternator is changed to increase the target voltage in the gradual generation, depending on the deterioration state of the battery. Or both are performed. Supply of power from the power supply unit to the electrical load is started after such setting change processing. By this, it is possible to reduce the concern that the output voltage of the battery may be interrupted at the time of starting the engine.

  The above object, other objects, features and advantages of the present invention will become more apparent from the detailed description of the following embodiments given with reference to the drawings.

It is a block diagram which shows a part of principal part structure of the vehicle of this Example. FIG. 7 is a flow chart showing a part of the operation of the ECU shown in FIG. 1; FIG. 7 is a flow chart showing another part of the operation of the ECU shown in FIG. 1; (A) is a map showing an example of the relationship between the engine rotational speed, the alternator temperature and the alternator current value, and (B) is a map showing another example of the relationship between the engine rotational speed, the alternator temperature and the alternator current value is there. (A) is a graph which shows an example of the time change of a battery voltage value, (B) is a graph which shows an example of the time change of a battery current value. It is a graph which shows an example of the relationship between a degradation resistance value and the degradation degree of a battery. It is a graph which shows an example of the time change of an alternator voltage value.

  Referring to FIG. 1, a vehicle 10 of this embodiment includes a four-stroke engine (internal combustion engine) 12 in which three cylinders 141 to 143 are formed as a power source.

  When an IG on operation is performed by an ignition key (not shown) or an idle start condition is satisfied in the idle stop state, the ECU 36 turns on the relay 28 to start the engine 12. The power of the battery 26 is supplied to the starter 30 via the relay 28 in the on state, and the starter 30 performs cranking by the power of the battery 26. The engine 12 is started by cranking, and pistons (not shown) provided in each of the cylinders 141 to 143 move up and down at a speed at which the crankshaft 16 can rotate at an idle speed.

  The CVT 18 intervenes between the crankshaft 16 and the propeller shaft 20. The rotational force of the crankshaft 16 is transmitted to the propeller shaft 20 at a gear ratio set for the CVT 18. The rotational force of the propeller shaft 20 is then transmitted to the tire via a drive shaft (not shown), whereby the vehicle 10 is advanced.

  Although the rotational speed of the crankshaft 16 corresponds to the rotational speed of the engine 12 (= engine rotational speed), the engine rotational speed changes according to the depression amount of the accelerator pedal (not shown) and is detected by the engine rotational sensor 34 Be done.

  The rotational force of the crankshaft 16 is also transmitted to the rotation shaft 24s of the alternator 24 via the belt 22. The alternator 24 performs gradually excitation power generation, and the output voltage value (= alternator voltage value) of the alternator 24 gradually rises to the target voltage value. The battery 26 is charged by the alternator 24 operating in this manner. The temperature of the alternator 24 (= alternator temperature) is detected by the temperature sensor 32.

  The electric loads mounted on the vehicle 10 include the essentials for driving such as engine drive parts (injectors, plugs, etc.), lights, VSC, that is, the essential equipment, and driver's comfort such as heat theta and air conditioner. There is equipment to enhance the character or comfort equipment. The power supply unit 38 supplies power to these devices based on the output voltage of the battery 26.

  As described above, since the alternator 24 performs the gradual excitation power generation, the output of the alternator 24 immediately after the engine 12 starts is much smaller than the output of the battery 26. Therefore, when the output of the battery 26 is reduced due to the deterioration of the battery 26, the electrical load may be relatively excessive, and the output of the battery 26 may be momentarily interrupted.

  Here, the priority for supplying power to essential equipment is much higher than the priority for supplying power to comfort equipment. Also, the need to power the vital equipment in response to the establishment of the idle start condition is much higher than the need to power the vital equipment in response to the IG on operation.

  Therefore, in this embodiment, when the idle start condition is satisfied in the idle stop state, the ECU 36 is caused to execute the vehicle control processing according to the flowcharts shown in FIGS. 2 and 3.

  The control program corresponding to this flowchart is stored in the memory 36m. Further, the rotational speed of the engine 12 and the temperature of the alternator 24 are repeatedly detected under another routine not shown.

  Furthermore, in the memory 36m, a map showing the relationship among the engine speed, the alternator temperature and the alternator current value (= the output current value of the alternator 24) is prepared for each battery voltage value (FIGS. 4A and 4). (B)).

  According to FIG. 4A, the alternator current value changes between I12 (1, 1) to I12 (7, 7) according to the engine speed and the alternator temperature. Moreover, according to FIG. 4 (B), an alternator electric current value changes between I13 (1, 1)-I13 (7, 7) according to an engine speed and alternator temperature.

  Referring to FIG. 2, in step S1, an output voltage value (= battery voltage value) of battery 26 is detected, and in step S3, an output current value (= battery current value) of battery 26 is detected. In step S5, the alternator temperature is acquired from another routine, and in step S7, the engine speed is acquired from another routine.

  In step S9, a map corresponding to the battery voltage value detected in step S1 is selected from the plurality of maps described above. In step S9, an alternator current value corresponding to the alternator temperature acquired in step S5 and the engine rotational speed detected in step S7 is estimated with reference to the selected map.

  In step S11, the battery voltage value detected in step S1 is divided by the battery current value detected in step S3 to calculate the resistance value, and the difference between the calculated resistance value and the predetermined resistance value is used as the deterioration resistance value. To detect.

  Here, the predetermined resistance value is a resistance value calculated from the battery voltage value and the battery current value detected when the battery 26 is new (SOC = 100%). The battery voltage value and the battery current value that define the predetermined resistance value change along the dotted lines drawn in FIG. 5A and FIG. 5B, and the battery voltage value and the battery current value that define the current resistance value When changing along the solid line depicted in FIG. 5A and FIG. 5B, the difference between the dotted line and the solid line corresponds to the degradation resistance value. Further, as can be seen from FIG. 6, the degree of deterioration of the battery 26 increases as the deterioration resistance value increases.

In step S13, the under voltage value is calculated according to equation 1.
[Equation 1]
Under voltage value = {K-Alternator current value} * Deterioration resistance value

  According to Equation 1, the alternator current value estimated in step S9 is subtracted from the constant K, and the subtraction value obtained thereby is multiplied by the deteriorated resistance value detected in step S11. The undervoltage value calculated in this manner is used to correct the target voltage value of the gradual excitation power generation by the alternator 24 in consideration of the deterioration of the battery 26.

  In step S15, it is determined whether the under voltage value exceeds 0V. If the determination result is NO, the process proceeds to step S17, and the setting of the alternator 24 is adjusted so that the target voltage value of the gradual excitation power generation can be adjusted to the initial value (see FIG. 7). In step S19, it is repeatedly determined whether the alternator voltage value has reached the target voltage value.

  If the determination result is from NO to YES, the power supply unit 38 is activated in step S21. The supply of power to the electrical load is initiated by the activation of the power supply unit 38. The vehicle control process ends after the power supply unit 38 is activated.

  On the other hand, if the determination result in step S15 is YES, the process proceeds to step S23, and it is determined whether the degradation resistance value is less than the threshold value TH1. If the determination result is YES, the process returns directly to step S19, while if the determination result is NO, the following processing is executed in steps S25 to S31, and then the process returns to step S19.

  That is, in step S25, the setting of the alternator 24 is adjusted so that the target voltage value of the gradual excitation power generation can be adjusted to the “initial value + undervoltage value” (see FIG. 7). In step S27, it is determined whether or not the deterioration resistance value falls below a threshold TH2 that is larger than the threshold TH1.

  If the determination result is NO, the process proceeds to step S29, and the setting of the power supply unit 38 is changed so that the operation of the comfortable equipment is weakened. On the other hand, if the determination result is YES, the setting of the power supply unit 38 is changed so that the comfortable equipment is stopped only for a predetermined period. The electrical load is thus limited in stages.

  As can be understood from the above description, in addition to the engine 12, the vehicle 10 also includes a power supply unit 38 for supplying power to the electric load based on the output voltage of the battery 26, and an alternator 24 for charging the battery 26 by gradual excitation. And are provided. When the engine 12 is started by the establishment of the idle start condition, the ECU 36 changes the setting of the power supply unit 38 so that the electric load is reduced and / or the alternator is increased so that the target voltage value in the gradual generation is increased. The process of changing the setting of 24 is executed in a different manner in accordance with the deterioration state of the battery 26 (S23 to S31). When such setting change processing is completed, the ECU 36 activates the power supply unit 38 (S21). By this, it is possible to reduce the concern that the output voltage of the battery 26 may be momentarily disconnected when the engine 12 is started.

10 ... vehicle 12 ... engine 24 ... alternator 26 ... battery 32 ... temperature sensor 34 ... engine rotation sensor 36 ... ECU
38 ... Power supply unit

Claims (1)

A vehicle control apparatus for controlling a vehicle comprising: a power supply unit for supplying electric power to an electric load based on an output voltage of a battery; and an alternator for charging the battery by gradual excitation power generation,
Changing the setting of the power supply unit so that the electric load is reduced when the engine is started and / or changing the setting of the alternator so that the target voltage in the gradual generation increases A vehicle control device comprising: setting change means which is executed in a different manner according to a deterioration state of the vehicle; and start means which starts the power supply unit after the process of the setting change means.

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