JP2003322040A - Control device of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for a vehicle capable of suppressing a rise of the battery temperature in association with the charge and discharge of a battery and thereby increasing the chance of engine stop. <P>SOLUTION: An electronic control unit (ECU) of this vehicle control device stops automatically the engine mounted in the vehicle when the automatic stopping conditions are met, including the condition that the temperature of the high voltage battery is lower than the upper limit value (Steps 110 and 120) and drives an auxiliary unit with the power supplied from the high voltage battery. When the automatically stopped time t of the engine has attained the specified limit time t0 (Step 180: YES), the ECU puts the engine automatically stopped in an automatic start with the power supplied from the battery (Step 190). After the automatic start, power generation is made in compliance with the vehicle running condition and the battery is charged. Further the ECU changes the limit time t0 in accordance with the battery temperature T sensed by a battery temperature sensor (Steps 130 and 140). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention stops an engine when a stop condition is satisfied, drives an auxiliary machine by supplying power from a battery, and supplies the engine with power supplied from a battery when a predetermined condition is satisfied. The present invention relates to a control device for a vehicle, which is started by the above-mentioned method, and further generates electric power according to a running state of the vehicle to charge a battery.

[0002]

2. Description of the Related Art As one form of a vehicle drive device, a structure in which a motor generator (MG) is connected to an engine is known. In this vehicle drive device, the MG and the accessory are connected by a power transmission mechanism such as a pulley and a belt, and the power transmission mechanism is connected to the crankshaft of the engine via a clutch. Therefore, when the clutch is connected, the engine can drive the auxiliary machine, and when the clutch is disengaged, only the MG can drive the auxiliary machine.

This vehicle drive device has conventionally been an economy running system (hereinafter referred to as "eco-run system").
Is used for. The eco-run system is an automatic stop and start system that enables the vehicle to start by automatically stopping the engine when the vehicle stops (stops) at an intersection or the like, and automatically starts the engine at the time of start operation for the purpose of improving fuel economy. is there. In this eco-run system, the clutch is disengaged while the engine is automatically stopped. The MG is driven by the electric power supplied from the battery, and the rotation thereof is transmitted to the auxiliary machine via the power transmission mechanism. Further, when the engine is automatically started, the clutch is engaged, and the crankshaft of the engine is forcedly rotated (cranked) by the MG. After the automatic start, the electric energy generated by the MG is stored in the battery.

Therefore, during the automatic stop, the battery is discharged by the power supply to the MG and the SOC (state of charge of the battery) is lowered, and after the automatic start, the battery is charged and the SOC is recovered.

By the way, the battery generates heat as it discharges during automatic stop and heat as it charges during operation after automatic start. These heat generations are mainly due to Joule heat when current flows through the conductor. The repeated charging and discharging causes the temperature of the battery to rise over time due to the heat generation, which causes the battery life to be shortened.

For this, for example, Japanese Patent Publication No. 3-466.
In Japanese Patent Publication No. 56, it is proposed that the engine is automatically stopped only when the battery temperature is within a setting range suitable for the use condition of the battery, that is, if the battery temperature is out of the setting range, automatic stop is prohibited. ing.

[0007]

However, according to the technique disclosed in the above publication, the engine is automatically stopped and automatically started regardless of the battery temperature until the battery temperature exceeds the upper limit of the set range. For this reason, the battery temperature reaches the upper limit value of the setting range in a relatively short time due to the repetition of automatic stop and automatic start, and thereafter, automatic stop is prohibited until the battery temperature falls and enters the setting range again. The Rukoto. As a result, the opportunity for automatic stop is greatly limited, the total automatic stop time is shortened, and the effect of improving fuel efficiency due to the automatic stop cannot be sufficiently obtained.

The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress the degree of increase in battery temperature due to charging / discharging of the battery and thus increase the chances of stopping the engine. It is to provide a control device.

[0009]

[Means for Solving the Problems] Means for achieving the above-mentioned objects and their effects will be described below. The invention according to claim 1 is applied to a vehicle provided with an engine, a battery for supplying electric power for driving an auxiliary machine and starting the engine, and a temperature detecting means for detecting the temperature of the battery. , Stopping in response to the establishment of a stop condition including the temperature of the battery being lower than the upper limit value by the temperature detecting means, driving the auxiliary machine by the power supply from the battery, and stopping the engine for a predetermined time. When the time limit of is reached, the stopped engine is started by the power supply from the battery, and the battery is charged by generating power according to the running state of the vehicle after the start. The control device further comprises time limit changing means for changing the time limit according to the temperature of the battery by the temperature detecting means. . Here, the traveling state of the vehicle after the start includes not only traveling of the vehicle but also traveling stop.

According to the above configuration, the engine is stopped when the stop condition including that the temperature of the battery is lower than the upper limit value is satisfied. During this stop, the auxiliary machine is driven by the power supply from the battery. Then, when the engine stop time reaches a predetermined time limit, the stopped engine is started by the power supply from the battery even if the engine start condition is not satisfied. This time limit is changed by the time limit changing means based on the temperature of the battery detected by the temperature detecting means.

Here, when the engine is stopped or the like, the battery is discharged by the power supply for driving the auxiliary machinery,
The state of charge (SOC) decreases. However, after starting, power is generated according to the running state of the vehicle, and the battery is charged. This charging restores the range of decrease in the SOC of the battery. Since both the charge and the above-mentioned discharge are accompanied by heat generation, the temperature of the battery rises as the charge and discharge are repeated by repeatedly stopping and starting the engine. The extent of this temperature rise, that is, the extent of heat generation, depends on the SOC recovery width associated with charging, that is, the SOC reduction width associated with discharging. The larger the decrease width and the recovery width are, the more heat is generated and the battery temperature becomes higher.

Therefore, depending on the length of the engine stop time, the amount of charge / discharge in the battery, the variation range of SOC, the amount of heat generation, etc. differ, and the degree of increase in battery temperature also varies. However, reflecting the battery temperature in the time limit as described above,
By setting the engine stop time to a value according to the battery temperature, it is possible to suppress the degree of increase in the battery temperature due to charging and discharging of the battery. As a result, it is possible to lengthen the time until the battery temperature reaches the upper limit value and increase the chances of stopping the engine. Also, for the crew,
It is possible to prevent discomfort due to prohibition of engine stop.

According to a second aspect of the present invention, in the first aspect of the present invention, the time limit changing means sets the time limit for stopping when the temperature of the battery by the temperature detecting means is higher than when it is low. It should be shortened.

According to the above arrangement, when the battery temperature is high, the engine stop time limit is shortened compared to when the battery temperature is low, so that the discharge amount of the battery is reduced and the SOC is reduced.
The decrease width and the recovery width are reduced. Therefore, the amount of heat generated by discharging and charging the battery is smaller than that in the case where the time limit is constant regardless of the battery temperature, and an increase in the battery temperature is suppressed. As a result, when the battery temperature is high, the individual engine stop time is shorter than when the battery temperature is low, but the opportunity (number of times) of engine stop can be increased.

According to the invention described in claim 3, an engine,
The present invention is applied to a vehicle provided with a battery that supplies electric power for driving an auxiliary machine and starting an engine, and a temperature detection unit that detects the temperature of the battery. Stopping in response to the establishment of a stop condition including lower than that, while driving the auxiliary machine by the power supply from the battery, when the discharge amount of the battery reaches a predetermined limit discharge amount, A control device for a vehicle, wherein the engine is started by power supply from the battery, and the battery is charged by generating power according to a running state of the vehicle after the start, the temperature detecting means comprising: A limit discharge amount changing means for changing the limit discharge amount according to the temperature of the battery is further provided. Here, the traveling state of the vehicle after the start includes not only traveling of the vehicle but also traveling stop.

According to the above configuration, the engine is stopped when the stop condition including that the temperature of the battery is lower than the upper limit value is satisfied. During this stop, the auxiliary machine is driven by the power supply from the battery. Then, when the discharge amount of the battery accompanying the power supply reaches a predetermined limit discharge amount, the stopped engine is started by the power supply from the battery even if the engine start condition is not satisfied. This limited discharge amount is changed by the limited discharge amount changing means based on the temperature of the battery detected by the temperature detecting means.

Here, when the engine is stopped or the like, the battery is discharged by the power supply for driving the auxiliary machinery,
Its SOC decreases. However, after starting, power is generated according to the running state of the vehicle, and the battery is charged. This charging restores the range of decrease in the SOC of the battery. Since this charging and the above-mentioned discharge also generate heat,
The temperature of the battery rises as charging and discharging are repeated by repeatedly stopping and starting the engine. The extent of this temperature rise, that is, the extent of heat generation, depends on the SOC recovery width associated with charging, that is, the SOC reduction width associated with discharging. The larger the decrease width and the recovery width are, the more heat is generated and the battery temperature becomes higher.

Therefore, the amount of charge, the variation range of SOC, the amount of heat generation, etc. differ depending on the amount of discharge of the battery, and the degree of increase in battery temperature also differs. However, by reflecting the battery temperature in the limited discharge amount and setting the battery discharge amount to a value according to the battery temperature as described above, it is possible to suppress the degree of increase in the battery temperature due to charging and discharging of the battery. Becomes As a result, it is possible to increase the time until the battery temperature reaches the upper limit value and increase the chance of stopping. Further, it is possible to prevent the occupant from feeling uncomfortable due to the prohibition of the engine stop.

According to a fourth aspect of the present invention, in the third aspect of the invention, the limiting discharge amount changing means limits the discharging of the battery when the temperature of the battery detected by the temperature detecting means is higher than when the temperature of the battery is low. The amount should be reduced.

According to the above configuration, when the battery temperature is high, the limited discharge amount is reduced as compared to when the battery temperature is low, so that the SOC decrease width and the recovery width are reduced. Therefore,
The amount of heat generated by discharging and charging the battery is smaller than that when the limited discharge amount is constant regardless of the battery temperature, and the rise in battery temperature is suppressed. As a result, when the battery temperature is high, the amount of discharge is smaller than when the battery temperature is low, and the individual engine stop time is shortened, but the opportunity (number of times) of engine stop can be increased.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A first embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, a vehicle 11 is equipped with an engine 12 as a prime mover. This engine 12
Then, the mixture of fuel and air injected from the fuel injection valve 13 is compressed by the piston in a combustion chamber (not shown). Further, a high voltage is output from the ignition coil 15 to the ignition plug 16 based on the drive signal from the igniter 14, and the air-fuel mixture is ignited by electric sparks of the ignition plug 16 and explodes and burns. The high-temperature and high-pressure combustion gas generated at this time causes the piston to reciprocate, and the crankshaft 17, which is the output shaft, is rotationally driven to obtain the driving force (torque) of the engine 12.

The rotation of the crankshaft 17 is changed by the transmission 18, and the rotation after the change is transmitted to drive wheels (not shown). In addition, the crankshaft 17 has an electromagnetic clutch 1
A crank pulley 21 is attached via 9. When the electromagnetic clutch 19 is energized, the crankshaft 17 and the crank pulley 21 are integrally rotatably connected to each other.
Power can be transmitted between 7 and 21. When the electromagnetic clutch 19 is de-energized, the connection is released and the power transmission between the crank shaft 17 and the crank pulley 21 is cut off.

An auxiliary machine 22 and a motor generator (hereinafter referred to as “MG”) 23 are arranged near the engine 12. Examples of the auxiliary machine 22 include a power steering pump, an air conditioner compressor, an engine oil pump, an engine water pump, and the like. A first pulley 25 is attached to the power input shaft 24 of the accessory 22.

The MG 23 operates as an electric motor when the auxiliary machine 22 is driven while the engine 12 is automatically stopped or when the engine 12 is automatically started. Here, the automatic stop is a stop mode different from a normal stop by a driver's switch operation. For example, during the temporary stop of the vehicle such as waiting for a signal while the vehicle is traveling, the engine 12 is used for the purpose of improving fuel consumption. Is to automatically stop the operation of. In addition, the automatic start is a mode of starting different from a normal start by the switch operation of the driver, and the operation of the engine 12 is automatically restarted in response to the start request of the driver during the automatic stop described above. Is.

Further, the MG 23 operates as an alternator (generator) which is driven by the engine 12 to generate electric power while the engine 12 is operating. A second pulley 27 is attached to the input / output shaft 26 of the MG 23. A transmission belt 28 is stretched around the first and second pulleys 25 and 27 and the crank pulley 21. The power transmission belt 28 enables power transmission from the crankshaft 17 to the auxiliary equipment 22, power transmission from the MG 23 to the auxiliary equipment 22, and power transmission between the crankshaft 17 and the MG 23. The form of these power transmissions is switched by connecting and disconnecting the electromagnetic clutch 19.

A high voltage battery 31 is connected to the MG 23 via an inverter 29. High voltage battery 3
1 is provided with a battery temperature sensor 32 as a temperature detecting means for detecting the temperature (battery temperature T). As the battery temperature sensor 32, one that directly detects the temperature of the battery liquid is preferable, but the high voltage battery 3
The temperature of the outer wall of the case 1 may be measured.
Inverter 29 makes the supply of electric energy from high-voltage battery 31 to MG 23 variable by a switching operation to make the rotation speed of MG 23 variable. Further, inverter 29 supplies the high voltage battery 31 with the electric power generated by MG 23 by the switching operation. The high-voltage battery 31 is used exclusively as a power source for driving the MG 23, and stores (charges) the generated power when the MG 23 operates as a generator. A low voltage battery 34 is connected to the high voltage battery 31 via a DC / DC converter 33 which is a kind of converter. The low voltage battery 34 is used as a power source for driving the ECU 35 and the like described later. The DC / DC converter 33 steps down the voltage of the high voltage battery 31 and charges the low voltage battery 34.

In order to control the above-mentioned various parts of the engine 12, the electromagnetic clutch 19, the inverter 29, etc., the vehicle 11
Is an electronic control unit (EC)
U) 35 is used. The ECU 35 is mainly composed of a microcomputer, and a central processing unit (CPU) performs arithmetic processing according to a control program, initial data, control map, etc. stored in a read-only memory (ROM), and outputs the arithmetic result. Based on this, various controls are executed. The calculation result by the CPU is temporarily stored in the random access memory (RAM).

Examples of control of each part of the engine 12 include fuel injection control and ignition timing control. In the fuel injection control, the ECU 35 obtains the basic injection amount based on the operating state of the engine 12, for example, the engine rotation speed, the accelerator opening (or intake pressure), and corrects the basic injection amount by various parameters such as the water temperature and the intake temperature. Calculate the fuel quantity.
The fuel injection valve 13 is operated for a time corresponding to this injected fuel amount.
Is energized to inject fuel. In the ignition timing control, the basic ignition timing is calculated based on the engine load such as the engine speed and the intake pressure, and the final ignition timing is obtained by correcting the basic ignition timing with various correction values. Then, the igniter 14 is driven and controlled according to the final ignition timing to ignite the ignition plug 16.

Next, the automatic stop processing and automatic start processing of the engine 12 executed by the ECU 35 will be described with reference to the flowchart of FIG. First, in step 110, the ECU 35 determines whether or not the automatic stop condition is satisfied. Here, in the automatic stop condition, the battery temperature T is set to a predetermined upper limit value Tmax (for example, 75
℃) is included as an essential condition.
As another automatic stop condition, for example, with respect to the position of the shift lever, the P (parking) range or the N (neutral) range, which is a non-driving range, is selected. Another example is that the D (drive) range is selected and the brake pressure is equal to or higher than a predetermined value. It should be noted that those excluding the above essential conditions are merely examples, and can be changed as appropriate. Also,
Other conditions may be added as automatic stop conditions.

If the automatic stop condition is not satisfied in step 110, the automatic stop / start processing routine is temporarily terminated, and if satisfied, the engine 1 is started in step 120.
2) Automatic stop processing is performed. For example, the fuel injection from the fuel injection valve 13 is stopped, and the ignition of the air-fuel mixture by the spark plug 16 is stopped. By stopping these, the operation of the engine 12 is automatically stopped. Further, the energization of the electromagnetic clutch 19 is stopped. When the energization is stopped, the electromagnetic clutch 19 is disengaged, and the power is not transmitted between the crank pulley 21 and the crankshaft 17.

Further, when a predetermined condition regarding the state of high-voltage battery 31 is satisfied, inverter 29 is arranged so that input / output shaft 26 of MG 23 rotates with a torque considering the load of auxiliary machine 22 and the like. A switching signal is output to. The predetermined conditions include, for example, that the voltage and temperature of the high-voltage battery 31 are good, and that the SOC is high.
(Battery charge state) is a certain value or more. By the energization control of the inverter 29 according to this signal, electric power is supplied from the high-voltage battery 31 to the MG 23, and the MG 23 operates as an electric motor. I / O shaft 26
Is transmitted to the power input shaft 24 through the second pulley 27, the transmission belt 28, the first pulley 25, etc.
Is driven. At this time, the crank pulley 21 idles on the crank shaft 17. The MG 23 does not need to drive the crankshaft 17, and the load on the MG 23 is reduced accordingly. As described above, during the automatic stop, the auxiliary machine 22 that has been driven by the engine 12 until then is driven by the MG 23 that receives power supply from the high-voltage battery 31.

Next, in step 130, the battery temperature T by the battery temperature sensor 32 is read, and in step 140, the time limit t0 is calculated and set based on the battery temperature T. Here, the time limit t0 is
It is used to limit the automatic stop time (automatic stop time t), and the map shown in FIG. 3, for example, is used in the calculation. The map predefines the relationship between the battery temperature T and the time limit t0. Specifically, in a region where the battery temperature T is lower than the first predetermined value T1, the time limit t0 is a constant value α. Also, the battery temperature T
In the region where is equal to or larger than the first predetermined value T1, the time limit t0 becomes shorter as the battery temperature T becomes higher. Then, the time limit t0 corresponding to the battery temperature T is obtained from this map and stored in the memory (RAM). The time limit t0 may be calculated according to a predetermined arithmetic expression instead of the map. Thus, the ECU 35 functions as a time limit changing means for changing the time limit t0 according to the battery temperature T.

Then, in step 150 of FIG.
A counter for counting the elapsed time after the establishment of the automatic stop condition, that is, the time during which the automatic stop processing is performed (automatic stop time t) is reset to zero. In step 160, it is determined whether the automatic start condition is not satisfied. Here, the automatic start condition is, for example, that the accelerator pedal is depressed or the brake pedal is returned in the vehicle 11 in the automatic stop process. When the determination condition of step 160 is satisfied (the automatic start condition is not satisfied), the counter is incremented by a predetermined value, for example, "1" in step 170.

In step 180, it is determined whether the automatic stop time t counted by the counter is longer than the time limit t0 set in step 140. This determination condition is not satisfied (t0 ≧
t), the process returns to step 160. Therefore, when the automatic start condition is not satisfied, the automatic stop processing is continued until the time limit t0 elapses after the automatic stop condition is satisfied.

When the automatic stop time t exceeds the time limit t0 and the determination condition of step 180 is satisfied, or when the automatic start condition is satisfied and the determination condition of step 160 is no longer satisfied, step 19
The process proceeds to 0 and the automatic start process is performed. For example, the electromagnetic clutch 19 is energized to connect the electromagnetic clutch 19, and a current command is output to the inverter 29 to drive the MG 23. By this drive, the rotation of the input / output shaft 26 of the MG 23 is transmitted to the crank shaft 17 via the second pulley 27, the transmission belt 28, the crank pulley 21, and the like. MG23
A sufficient torque is transmitted from the engine to start the engine 12, and the crankshaft 17 is forcibly rotated to perform cranking. At this time, since the first pulley 25 also rotates, the auxiliary machine 22 is driven at the same time. When the engine rotation speed reaches a predetermined value, the fuel injection control and the ignition timing control at the start are executed to automatically start the engine 12. After the processing of step 190, the automatic stop / start processing routine is once ended. In this way, the MG 23 is driven by the power supply from the high-voltage battery 31, and the engine 12 that is being automatically stopped is automatically started.

It should be noted that the engine 1 after the cranking is completed.
After 2 is started, normal fuel injection control, ignition timing control, etc. are performed. Here, when the high voltage battery 31 supplies power to the MG 23 while the engine 12 is automatically stopped, the high voltage battery 31 is discharged and the SOC is reduced. Therefore, when the engine is running after the automatic start,
When the OC is lowered, the MG 23 is caused to function as a generator, and the high-voltage battery 31 is charged (charged) with the electric energy generated by the power generation. That is, the vehicle 11
The high voltage battery 31 is charged by generating power according to the running state of the vehicle. The S of the high voltage battery 31 lowered by the discharge
OC is restored by this charge.

According to the first embodiment detailed above, the following effects can be obtained. (1) The discharge of the high voltage battery 31 during the automatic stop of the engine 12 also causes the high voltage battery 3 after the automatic start.
Since the charging of No. 1 is also accompanied by heat generation, the temperature of the high-voltage battery 31 rises as charging and discharging are repeated by repeating automatic stop and automatic start. The degree of this temperature rise,
That is, the degree of heat generation varies depending on the SOC recovery width associated with charging, that is, the SOC reduction width associated with discharging. The larger the decrease width and the recovery width, the more heat is generated,
The battery temperature T becomes high. Therefore, depending on the length of the automatic stop time t, the charge / discharge amount in the high voltage battery 31, S
The change width of OC, the amount of heat generation, and the like are different, and the degree of increase in the battery temperature T is different.

On the other hand, in the first embodiment, the time limit t0 is changed according to the battery temperature T.
Therefore, the battery temperature T is set to the time limit t0 as described above.
By setting the automatic stop time t of the engine 12 to a value according to the battery temperature T, it is possible to suppress the degree of increase in the battery temperature T due to charging and discharging of the high-voltage battery 31. As a result, the battery temperature T becomes the upper limit value T
It is possible to increase the time to reach max and increase the chances of automatic stop. Further, along with this, it is possible to prevent the occupant from feeling uncomfortable due to the prohibition of automatic stop.

(2) In particular, in the region of T1≤T, when the battery temperature T is high, the time limit t is longer than when it is low.
0 is shortened. With this setting, when the battery temperature T is high, the amount of discharge of the high-voltage battery 31 is smaller than when it is low, and the range of decrease in SOC and the range of recovery are small. Therefore, the amount of heat generated by discharging and charging the high-voltage battery 31 is smaller in the region of T1 ≦ T than when the time limit t0 is constant (for example, the value α) regardless of the battery temperature T. , Battery temperature T
Rise is suppressed. As a result, although the individual automatic stop time t becomes shorter as the battery temperature T becomes higher, the opportunity (number of times) of automatic stop can be increased, and the merit of eco-run can be sufficiently obtained.

(3) In the region where the battery temperature T is equal to or higher than the first predetermined value T1, the automatic stop time t is shortened by shortening the time limit t0 as the battery temperature T increases. Therefore, as the battery temperature T increases, the degree of increase can be effectively moderated, and the time until the upper limit value Tmax is reached can be lengthened.

Here, when the time limit t0 is a constant value regardless of the battery temperature T, the change in the battery temperature T is shown by a chain double-dashed line (see comparative example) in FIG.
In the comparative example, the battery temperature T reaches the upper limit value Tmax in a relatively short time. Therefore, after that, the automatic stop is prohibited and the opportunity (number of times) is limited.

Further, when the time limit t0 is shortened as the battery temperature T becomes higher, the change in the battery temperature T is shown by a solid line (see the embodiment) in FIG. In FIG. 4, for example, the period from timing t1 to t2, from t3 to
During the period of t4, the period of t5 to t6, etc., the automatic stop is performed and the SOC decreases. The time of each of these periods is the time limit t
Equivalent to 0. As is clear from FIG. 4, in the embodiment,
As the battery temperature T increases, the automatic stop is performed in small increments, and the automatic stop time t gradually shortens. Therefore, in a region where the battery temperature T is high, the degree of increase is smaller than that in the comparative example, that is, the temperature rise is gentle and the time until the upper limit value Tmax is reached becomes longer. As a result, it is possible to effectively increase the chances of automatic stop.

(Second Embodiment) Next, a second embodiment of the present invention will be described. First of the second embodiment
The main difference from the embodiment is that a current sensor 36 for detecting the current i of the high-voltage battery 31 is provided as shown by the chain double-dashed line in FIG. The point is that the limited discharge amount d0 of the high-voltage battery 31 is used instead of the time t0. Here, the limited discharge amount d0 is used to limit the discharge amount of the high voltage battery 31, that is, the SOC usage range.

Next, this automatic stop / start processing routine will be described with reference to FIG. In addition, about the same process demonstrated by 1st Embodiment, the same number of steps is attached | subjected and detailed description is abbreviate | omitted.

The ECU 35 executes steps 110, 120, 1
After sequentially performing the processing of step 30, in step 145, the limited discharge amount d is determined based on the battery temperature T in step 130.
Calculate and set 0. When calculating the limited discharge amount d0, for example, the map shown in FIG. 5 is used. This map predefines the relationship between the battery temperature T and the limited discharge amount d0. Specifically, in a region where the battery temperature T is lower than the second predetermined value T2, the limited discharge amount d0 is a constant value β. Further, in the region where the battery temperature T is equal to or higher than the second predetermined value T2, the limited discharge amount d0 decreases as the battery temperature T increases. Then, the limited discharge amount d0 corresponding to the battery temperature T is obtained from this map and stored in the memory (RAM). The limited discharge amount d0 may be calculated according to a predetermined arithmetic expression instead of the map. In this way, the ECU 35 functions as a limited discharge amount changing unit that changes the limited discharge amount d0 according to the battery temperature T.

Then, in step 155 of FIG.
The discharge amount d obtained at the previous automatic stop is reset to 0. In step 160, it is determined whether or not the automatic start condition is not satisfied (not satisfied), and if not satisfied (step 160: YES), the discharge amount d associated with the automatic stop at this time is calculated in step 175. To do. For example, by reading the current i of the high-voltage battery 31 detected by the current sensor 36 at regular time intervals and integrating it,
The integrated value can be used as the discharge amount d.

Then, in step 185, it is determined whether or not the discharge amount d in step 175 is larger than the limited discharge amount d0 set in step 145.
If this determination condition is not satisfied (d0 ≧ d), there is still room for discharge, and the process returns to step 160.
Therefore, when the automatic start condition is not satisfied, the automatic stop process is continued until the discharge amount d after the automatic stop condition is satisfied becomes larger than the limited discharge amount d0.

When the determination condition of step 185 is satisfied or when the automatic start condition is satisfied, step 160
If the judgment condition of is not satisfied, step 1
The process proceeds to 90 and the automatic start process is performed. In this way, when the automatic start condition is satisfied, the engine 12 that is being automatically stopped is automatically started by the power supply from the high voltage battery 31. Further, before the automatic start condition is satisfied, the discharge amount d of the high voltage battery 31 accompanying the power supply is limited to the limited discharge amount d0.
Even when it reaches, the engine 12 that is automatically stopped is automatically started by the MG 23 that is supplied with power from the high-voltage battery 31. When the processing of step 190 has been performed or when the determination condition of step 110 is not satisfied, the automatic stop / start processing routine is once ended.

According to the second embodiment described in detail above, the following effects can be obtained. (4) Since the high-voltage battery 31 is discharged while the engine 12 is automatically stopped and the high-voltage battery 31 is charged after the engine 12 is automatically started, heat is charged and discharged by repeating the automatic stop and automatic start of the engine 12. Is repeated, the battery temperature T rises. The extent of this temperature rise, that is, the extent of heat generation, depends on the SOC recovery width associated with charging, that is, the SOC reduction width associated with discharging. The larger the decrease width and the recovery width are, the more heat is generated and the battery temperature T becomes higher. Therefore,
The variation range of SOC according to the discharge amount of the high-voltage battery 31,
The amount of heat generation is different, and the degree of increase in the battery temperature T is different.

On the other hand, in the second embodiment, the limited discharge amount d0 is changed according to the battery temperature T. Therefore, as described above, the battery temperature T is reflected in the limited discharge amount d0, and the discharge amount d of the high-voltage battery 31 is set to a value corresponding to the battery temperature T. It is possible to suppress the degree of increase in the temperature T. As a result, the battery temperature T becomes the upper limit value Tma.
It is possible to increase the time to reach x and increase the chance of automatic stop. Further, along with this, it is possible to prevent the occupant from feeling uncomfortable due to the prohibition of automatic stop.

(5) In particular, in the region of T2≤T, when the battery temperature T is high, the limited discharge amount d0 is smaller than when it is low. With this setting, when the battery temperature T is high, the discharge amount d of the high-voltage battery 31 is suppressed more than when it is low, and the SOC reduction width and the recovery width are reduced. Therefore, the amount of heat generated by discharging and charging the high-voltage battery 31 is smaller than in the case where the limited discharge amount d0 is a constant value β regardless of the battery temperature T, even in the region of T2 ≦ T. The rise of T is suppressed. As a result, when the battery temperature T is high, the discharge amount d becomes smaller than when the battery temperature T is low, and the individual automatic stop time t becomes shorter as in the first embodiment. However, the opportunity (number of times) of automatic stop can be increased, and the merit of eco-run can be fully obtained.

(6) In the region where the battery temperature T is equal to or higher than the second predetermined value T2, the discharge amount d is reduced by decreasing the limited discharge amount d0 as the battery temperature T increases. Therefore, as the battery temperature T increases, the degree of increase can be effectively moderated, and the time until the upper limit value Tmax is reached can be lengthened. As a result, it is possible to effectively increase the chances of automatic stop.

The present invention can be embodied in another embodiment shown below. In the first embodiment, in the region of T1> T in FIG. 3,
The time limit t0 is a constant value α regardless of the battery temperature T.
And Alternatively, in the same region, the time limit t0 may be shorter when the battery temperature T is high than when it is low.

The region of T1≤T in FIG. 3 may be divided into a plurality of regions, and the time limit t0 may be set for each of the divided regions. In this case, the time limit t0 is shortened as the battery temperature T increases.

In the region of T1≤T in FIG. 3, the degree of change of the time limit t0 with respect to the battery temperature T may be changed according to the battery temperature T. That is, the characteristics of the map in the same area may be changed non-linearly.

In the second embodiment, in the region of T2> T in FIG. 5, the limited discharge amount d0 is set to a constant value β regardless of the battery temperature T. Alternatively, in the same region, the limited discharge amount d0 may be smaller when the battery temperature T is high than when it is low.

The region of T2≤T in FIG. 5 may be divided into a plurality of regions, and the limited discharge amount d0 may be set for each of the divided regions. In this case, the limited discharge amount d0 is decreased as the battery temperature T increases.

In the region of T2 ≦ T in FIG. 5, the degree of change of the limited discharge amount d0 with respect to the battery temperature T may be changed according to the battery temperature T. That is, the characteristics of the map in the same area may be changed non-linearly.

The contents of the first embodiment and the contents of the second embodiment may be combined. That is, the automatic start process is performed when either (a) the automatic stop time t reaches the time limit t0 or (b) the discharge amount d reaches the limit discharge amount d0 first. To do. In this case, making the time limit t0 and the discharge amount d variable according to the battery temperature T is the same as in the first and second embodiments.

The present invention can be applied to a vehicle having an eco-run system of a type in which an engine is started by a motor but wheels are not driven. Further, the invention can be applied to a vehicle (corresponding to the above embodiment) having an eco-run system of a type in which an engine is started by a motor and wheels are driven.

Other technical ideas that can be understood from the above-described embodiments will be described together with their effects. (A) In the vehicle control device according to claim 2, in the region where the temperature of the battery is equal to or higher than a first predetermined value, the time limit changing means shortens the time limit for stopping as the temperature increases. .

According to the above configuration, the stop time is shortened as the battery temperature rises, so that the degree of increase can be moderated as the battery temperature rises, and the chance of stopping can be effectively increased.

(B) In the control device for a vehicle according to claim 4, in the region where the temperature of the battery is equal to or higher than the second predetermined value, the limiting discharge amount changing means limits the battery as the temperature increases. Reduce the amount of discharge.

According to the above arrangement, the amount of discharge is reduced as the battery temperature rises to shorten the stop time, and the degree of rise can be moderated as the battery temperature rises, effectively providing an opportunity to stop. You can increase.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the configuration of a first embodiment of a vehicle control device of the present invention.

FIG. 2 is a flowchart illustrating a procedure for controlling automatic stop and automatic start of an engine.

FIG. 3 is a schematic diagram showing a map structure of a map used for determining a time limit t0.

FIG. 4 is a timing chart showing changes in battery temperature and SOC.

FIG. 5 is a schematic diagram showing a map structure of a map used for determining a limited discharge amount in the second embodiment.

FIG. 6 is a flowchart illustrating a procedure for controlling automatic stop and automatic start of the engine.

[Explanation of symbols]

11 ... Vehicle, 12 ... Engine, 22 ... Auxiliary equipment, 31 ... High-voltage battery, 32 ... Battery temperature sensor, 35 ... EC
U, T ... Battery temperature, t0 ... Time limit, t ... Automatic stop time, d0 ... Limited discharge amount, d ... Discharge amount, Tmax ... Upper limit value.

Continued front page    F-term (reference) 3G092 AC02 AC03 CA02 EA09 EA17                       FA30 GA10 HA04Z HE01Z                       HE08Z HF02Z HF12Z                 3G093 AA05 AA07 AA16 BA21 BA22                       DA01 DA04 DA05 DA06 DB09                       DB11 DB23 EB00 FA10 FA11

Claims (4)

[Claims] 1. A vehicle equipped with an engine, a battery for supplying electric power for driving an auxiliary machine and starting the engine, and temperature detecting means for detecting the temperature of the battery. The battery is stopped by the means in response to the establishment of a stop condition including the temperature being lower than the upper limit value, the auxiliary machine is driven by the power supply from the battery, and the engine stop time is set to a predetermined time limit. When it reaches, the control device for the vehicle is configured to start the stopped engine by supplying electric power from the battery, and generate power according to the running state of the vehicle after the start to charge the battery. And a time limit changing means for changing the time limit according to the temperature of the battery by the temperature detecting means. Control device. 2. The vehicle control device according to claim 1, wherein the time limit changing means shortens the time limit for stopping when the temperature of the battery detected by the temperature detecting means is high compared to when the temperature of the battery is low. 3. A vehicle equipped with an engine, a battery for supplying electric power for driving an auxiliary machine and starting the engine, and temperature detecting means for detecting the temperature of the battery. The battery is stopped according to the establishment of a stop condition including that the temperature of the battery is lower than the upper limit value, the auxiliary machine is driven by the power supply from the battery, and the discharge amount of the battery is a predetermined limit discharge amount When the vehicle reaches, the control device for the vehicle is configured to start the stopped engine by supplying power from the battery, and generate power according to the running state of the vehicle after the start to charge the battery. A vehicle characterized by further comprising limit discharge amount changing means for changing the limit discharge amount according to the temperature of the battery by the temperature detecting means. Both controllers. 4. The limited discharge amount changing means reduces the limited discharge amount of the battery when the temperature of the battery detected by the temperature detecting means is high compared to when the temperature of the battery is low.
The control device for a vehicle according to item 1.