JP2007056745A - Controller for idle stop vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent much time from being required until permission of idle stop when SOC of a battery is high. <P>SOLUTION: It is determined whether SOC of the battery pack 1 is above a predetermined value or not. If SOC is above the predetermined value, idle stop is permitted irrespective of the integration amount of charging and discharging current. On the other hand, if SOC of the battery pack 1 is less than the predetermined value, the integration amount of charging and discharging current is computed to permit idle stop if the computed amount of integration is above predetermined amount. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control device for an idle stop vehicle.

  2. Description of the Related Art Conventionally, a system that calculates an integrated amount of charge / discharge current of a battery and permits an idle stop of a vehicle if the integrated amount of charge / discharge current is equal to or greater than a predetermined amount is known (see Patent Document 1).

JP 2001-224103 A

  However, when the charge capacity of the battery is close to the full charge capacity, there is a problem that it takes time until the idling stop is permitted because the rate of increase of the current integrated amount at the time of charging becomes slow. .

  The control device for the idle stop vehicle according to the present invention is a device that permits idling of the vehicle if the integrated amount of the charge / discharge current of the battery is equal to or greater than a predetermined amount. The vehicle is allowed to be idle-stopped regardless of the integrated amount of current.

  According to the control apparatus for an idle stop vehicle according to the present invention, if the SOC of the battery is equal to or greater than a predetermined value, the idle stop of the vehicle is permitted regardless of the integrated amount of charge / discharge current. In this state, the idle stop can be permitted quickly.

  FIG. 1 is a diagram illustrating a configuration of a control device for an idle stop vehicle according to an embodiment. The assembled battery 1 is configured by connecting n (n is a natural number) cells C1 to Cn in series. The DC voltage of the assembled battery 1 is converted into an AC voltage by the inverter 4 and applied to an AC motor 5 that is a driving source of the vehicle. A driving force obtained from the AC motor 5 and / or a driving force obtained from the engine 11 is transmitted to a wheel (not shown) via the transmission 10.

  The AC motor 12 is a motor generator that functions as a generator using the engine 11 as a power source and also functions as a starting motor for starting the engine 11. The control unit 3 includes a CPU 3a, a ROM 3b, and a RAM 3c, and controls the inverter 4 to charge and discharge the assembled battery 1. The control unit 3 also controls permission / prohibition of idle stop of the vehicle by a method described later.

  The voltage sensor 6 detects the total voltage Vbat of the assembled battery 1 and outputs it to the control unit 3. The current sensor 7 detects a charging current flowing through the assembled battery 1 and a discharging current flowing from the assembled battery 1 (hereinafter collectively referred to as a charging / discharging current Ibat) and outputs the detected current to the control unit 3. Here, the charging current is detected as a positive value, and the discharging current is detected as a negative value.

  FIG. 2 is a flowchart showing the contents of processing performed by the control device for the idle stop vehicle in the embodiment. When the vehicle is activated, the CPU 3a of the control unit 3 starts the process of step S10. In step S10, it is determined whether the assembled battery 1 has deteriorated. For example, if the cumulative travel distance of the vehicle is equal to or greater than a predetermined distance, it is determined that the assembled battery 1 has deteriorated. If the travel distance is less than the predetermined distance, it is determined that the assembled battery 1 has not deteriorated. If it determines with the assembled battery 1 having deteriorated, it will progress to step S100.

  In step S100, an idle stop permission flag is set to 0. The idle stop permission flag is a flag indicating whether or not the idle stop is permitted. When the flag value is 0, the idle stop is prohibited. When the flag value is 1, the idle stop is permitted. To do. Note that the initial value of the idle stop permission flag is 0.

  On the other hand, if it determines with the assembled battery 1 not having deteriorated in step S10, it will progress to step S20. In step S20, it is determined whether or not the SOC of the battery pack 1 is equal to or greater than a predetermined value. The SOC of the assembled battery 1 is obtained, for example, by preparing a table showing the relationship between the total voltage of the assembled battery 1 and the SOC in advance and referring to the table based on the voltage value detected by the voltage sensor 6. be able to. If it is determined that the SOC of the assembled battery 1 is equal to or greater than the predetermined value, the process proceeds to step S50, and if it is determined that the SOC is less than the predetermined value, the process returns to step S30.

In step S30, the current sensor 7 detects the charge / discharge current Ibat of the assembled battery 1, and obtains the integrated value It of the charge / discharge current from the following equation (1). However, Δt is the time interval (sampling time) at which the current sensor 7 detects the charge / discharge current, and the initial value of It is 0.
It = It + Ibat · Δt (1)

  In step S40 following step S30, it is determined whether the integrated value It of charge / discharge current calculated in step S30 is equal to or greater than a predetermined value. This predetermined value is determined in advance in consideration of the capacity of the assembled battery required when starting the engine, the capacity of the assembled battery required when performing idle stop for a predetermined time, and the like. If it determines with integrated value It of charging / discharging electric current being more than predetermined value, it will progress to step S50, and if it determines with it being less than predetermined value, it will return to step S30.

  In step S50, the idle stop permission flag is set to 1, and the process proceeds to step S60. In step S60, it is determined whether or not a predetermined idle stop condition is satisfied. If it is determined that the predetermined idle stop condition is not satisfied, the process waits in step S60. If it is determined that the predetermined idle stop condition is satisfied, the process proceeds to step S70.

  In step S70, idle stop is performed to temporarily stop the engine 11. When the idle stop is performed, the process proceeds to step S80. In step S80, it is determined whether or not a predetermined idle stop cancellation condition is satisfied. If it is determined that the predetermined idle stop cancellation condition is not satisfied, the process waits in step S80. If it is determined that the predetermined idle stop cancellation condition is satisfied, the engine 11 is restarted and the process proceeds to step S90.

  In step S90, it is determined whether or not a vehicle key switch (not shown) is turned off. If it is determined that the key switch is not turned off, the process returns to step S10. If it is determined that the key switch is turned off, the process of the flowchart shown in FIG.

  FIG. 3 is a diagram showing a change with time of the integrated charge / discharge current value. When the SOC of the battery pack 1 is high (when the SOC is equal to or higher than a predetermined value), the result is a solid line, and when the SOC is low (the SOC is a predetermined value) The results are shown by dotted lines. As shown in FIG. 3, when the SOC of the battery pack 1 is high, the degree of increase in the accumulated charge / discharge current amount is smaller than when the SOC is low. Therefore, as in the conventional control device, if the condition that the charge / discharge current integrated amount is equal to or greater than a predetermined value is provided as a condition for permitting the idle stop, the idle stop is permitted when the SOC of the assembled battery 1 is high. Takes time.

  FIG. 4 is a diagram showing the time change of the SOC of the battery pack 1. Lines L1 and L2 indicating the time change of the SOC respectively show the control results by the control device for the idle stop vehicle in the embodiment, and a line L3 indicating the time change of the SOC is an idle stop permission condition. This is a result in the case where the condition that the integrated current amount is not less than a predetermined value is not provided. If the condition that the accumulated current amount is not less than a predetermined value is not provided as the condition for permitting the idle stop, the idle stop is frequently performed, and the SOC of the assembled battery 1 is reduced.

  According to the control apparatus for the idle stop vehicle in the embodiment, if the integrated amount of the charge / discharge current of the assembled battery 1 is equal to or greater than a predetermined amount, the SOC of the assembled battery 1 is predetermined in the apparatus that permits the idle stop of the vehicle. If the value is greater than or equal to the value, the vehicle is allowed to stop idling regardless of the integrated amount of charge / discharge current. Thereby, when the SOC of the assembled battery 1 is in a state equal to or higher than a predetermined value, the idle stop can be permitted quickly, which can contribute to an improvement in fuel consumption. When the SOC is equal to or greater than a predetermined value, the vehicle is not affected even if the SOC of the battery pack 1 is reduced due to idle stop.

  Further, according to the control device for the idle stop vehicle in the embodiment, if the SOC of the assembled battery 1 is less than the predetermined value, the idle stop is permitted when the integrated amount of the charge / discharge current is equal to or greater than the predetermined amount. Therefore, it is possible to prevent the SOC of the battery pack 1 from continuing to decrease due to frequent idle stops.

  Further, according to the control apparatus for the idle stop vehicle in the embodiment, when it is determined that the assembled battery 1 is deteriorated, the idle stop is prohibited, and therefore the engine cannot be restarted due to the deterioration of the assembled battery. Can be prevented in advance.

  The present invention is not limited to the embodiment described above. For example, whether or not the assembled battery 1 is deteriorated is determined based on the travel distance of the vehicle, but is determined by another method such as determining the internal resistance of the assembled battery 1 and determining based on the internal resistance. You can also.

  The correspondence between the constituent elements of the claims and the constituent elements of the embodiment is as follows. That is, the control unit 3 constitutes an SOC calculation means, an idle stop permission means, a charge / discharge current integrated amount calculation means, and a deterioration determination means. In addition, the above description is an example to the last, and when interpreting invention, it is not limited to the correspondence of the component of said embodiment and the component of this invention at all.

The figure which shows the structure of the control apparatus of the idle stop vehicle in one embodiment. The flowchart which shows the processing content performed by the control apparatus of the idle stop vehicle in one embodiment Figure showing the time change of charge / discharge current integrated value The figure which shows the time change of SOC of an assembled battery

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Battery assembly, 3 ... Control unit, 4 ... Inverter, 5 ... AC motor, 6 ... Voltage sensor, 7 ... Current sensor, 10 ... Transmission, 11 ... Engine, 12 ... AC motor, C1-Cn ... Cell

Claims (4)

If the accumulated amount of the charging / discharging current of the battery is equal to or greater than a predetermined amount,
SOC calculating means for calculating the SOC of the battery;
An idle stop vehicle comprising: an idle stop permission means for permitting an idle stop of the vehicle regardless of an integrated amount of charge / discharge current if the SOC calculated by the SOC calculation means is equal to or greater than a predetermined value. Control device. The control apparatus for an idle stop vehicle according to claim 1,
Charge charge / discharge current integrated amount calculating means for calculating the charge / discharge current integrated amount is further provided,
The idle stop permission means, when the SOC calculated by the SOC calculation means is less than a predetermined value, the charge / discharge current integrated amount calculated by the charge / discharge current integrated amount calculation means is greater than or equal to a predetermined amount. A control device for an idle stop vehicle, wherein the idle stop of the vehicle is permitted. In the control apparatus of the idle stop vehicle according to claim 1 or 2,
A deterioration determining means for determining whether or not the battery is deteriorated;
The idle stop permission means can calculate the integrated amount of charge / discharge current when it is determined by the deterioration determination means that the battery has not deteriorated and the SOC calculated by the SOC calculation means is equal to or greater than a predetermined value. And a control device for an idle stop vehicle, wherein the idle stop of the vehicle is permitted. In the control apparatus of the idle stop vehicle according to claim 3,
The idle stop vehicle control device according to claim 1, wherein the idle stop permission unit prohibits the idle stop of the vehicle when the deterioration determination unit determines that the battery is deteriorated.

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