Control device for vehicle

Abstract

To provide a control device for a vehicle capable of appropriately protecting a battery by preventing an excess of power limit of the battery, targeted at the vehicle that performs idling stop.SOLUTION: In a control device for a vehicle that includes an engine, a motor coupled to a crank shaft of the engine and capable of driving the crank shaft of the engine at start of the engine and a battery capable of providing / receiving electric power for / from the motor and that performs idling stop control for automatically stopping and restarting the engine, on the basis of a temperature of the battery, restarting electric power required for completing restart in the idling stop control is calculated, and whether or not the calculated restart electric power can be supplied from the battery is determined. When a determination that the restart electric power cannot be supplied from the battery is made, execution of the idling stop control is prohibited (Step S5).SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a control device for a vehicle that executes an idling stop for automatically stopping and restarting the operation of an engine.

Background Art

[0002] Patent Document 1 describes a battery monitoring device aimed at implementing an effective heat countermeasure against an abnormal heat generation phenomenon of a battery. The battery monitoring device described in this Patent Document 1 is a device that monitors a rechargeable battery, and includes a factor monitoring unit that monitors factors leading to an abnormal heat generation phenomenon in which the temperature of the battery continues to rise unintentionally. The factor monitoring unit has a deposition amount detection unit and an internal resistance detection unit. Further, the battery monitoring device includes an abnormality detection unit (monitoring module) that is electrically connected to the battery and detects an abnormality of the battery. The monitoring module suppresses the occurrence of the abnormal heat generation phenomenon based on the monitoring results of the factors leading to the abnormal heat generation phenomenon, and, for example, when a factor leading to an abnormal heat generation phenomenon in which the temperature of the battery rises excessively is discovered, implements a countermeasure against the abnormal heat generation phenomenon.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a vehicle temporarily stops due to waiting for a signal or the like, in a vehicle that implements an idling stop (S&S: Stop & Start) that automatically stops and restarts the engine operation, electric power supplied from the battery is used to drive a starter motor or a drive motor connected to the engine to start (crank) the engine. It is possible to apply a battery monitoring device as described in Patent Document 1 above to a vehicle equipped with such an idling stop function to protect the battery that supplies electric power to the starter motor or the drive motor. However, when restarting the engine in such an idling stop, like the battery monitoring device described in Patent Document 1 above, in the control that detects an abnormality in the battery temperature and feedbacks the detection result to deal with the abnormality, the feedback may not be in time, and there is a possibility that appropriate measures against the abnormality cannot be implemented.

[0005] For example, in an idling stop for a vehicle equipped with a "48V hybrid system" as shown in FIG. 1 (the detailed configuration will be described later), as shown in the time chart of FIG. 2, after automatically stopping the engine at time t1, from time t2 to time t3, the engine is restarted by a motor generator (48V·MG). At this time, for example, the input / output of the battery (48V·Battery) is restricted due to factors such as the temperature rise of the battery, and the engine start by the motor generator may fail. In such a case, from time t3 to time t4, the starter motor (Starter) is started to restart the engine. That is, it is fed back that the input / output restriction of the battery has occurred, and the engine start is switched from the motor generator to the starter motor. However, in the conventional control technology, before switching from the motor generator and starting the starter motor, the above-mentioned feedback is not in time, and the DC-DC converter operates. As a result, there is a possibility of exceeding the limited power of the 48V battery, and there is a risk that the battery cannot be properly protected.

[0006] The present invention has been conceived by focusing on the above technical problems, and aims to provide a vehicle control device that can prevent the excessive power limitation of a battery and appropriately protect the battery for a vehicle that performs idling stop.

Means for Solving the Problems

[0007] In order to achieve the above object, the present invention provides a vehicle control device that includes an engine, a motor connected to the crankshaft of the engine and capable of driving the crankshaft when starting the engine, and a battery capable of supplying and receiving electric power to and from the motor, and performs idling stop control for automatically stopping and restarting the engine. The device includes a controller that controls the engine, the motor, and the battery and executes the idling stop control when a predetermined automatic stop condition is satisfied. The automatic stop condition includes that the restart power required until the restart is completed in the idling stop control can be supplied from the battery. The controller calculates the restart power based on at least the temperature of the battery, determines whether the calculated restart power can be supplied from the battery, and when it is determined that the restart power cannot be supplied from the battery, determines that the automatic stop condition is not satisfied and prohibits the execution of the idling stop control. It is characterized by the above.

Effects of the Invention

[0008] The vehicle control device of the present invention controls a vehicle that performs idling stop control, and executes idling stop control and battery protection control for the battery used in the idling stop control. The battery protection control determines whether the power required until the end of the idling stop control, that is, the restart power, can be secured by the battery based on at least the temperature of the battery. And when it is determined that the restart power cannot be secured by the battery, the execution of the idling stop control is prohibited to prevent the battery from exceeding its power limit.

[0009] Therefore, according to the vehicle control device of the present invention, it is possible to prevent the battery from exceeding its power limit and appropriately protect the battery for a vehicle that performs idling stop.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0011] Embodiments of the present invention will be described with reference to the drawings. Note that the embodiments described below are merely examples of implementing the present invention and do not limit the present invention.

[0012] The vehicle to be controlled in the embodiments of the present invention is equipped with at least an engine (internal combustion engine) as a driving force source, and when starting the engine, it is provided with a motor capable of cranking the engine. The motor is connected to the crankshaft of the engine so as to be able to transmit power. And it is provided with a battery capable of exchanging electric power with the motor. Note that the motor may be provided specifically for starting the engine as a so-called "starter motor", or it may be a motor of a driving force source that drives the engine and outputs the driving torque of the vehicle. That is, the vehicle to be controlled in the embodiments of the present invention may be a hybrid vehicle equipped with an engine and the above-described motor as driving force sources. FIG. 1 shows an example of a vehicle to be controlled in the embodiments of the present invention.

[0013] The vehicle Ve shown in FIG. 1 is a hybrid vehicle equipped with a hybrid system called a so-called mild hybrid or 48V hybrid, etc., and is provided with an engine (ENG) 1 and a motor (48V·MG) 2 as driving force sources. The vehicle Ve is also provided with a driving battery (48V·Battery) 3 and an automatic transmission (T / M) 4. And the vehicle Ve is provided with a detection unit 5 and a controller (ECU) 6 in order to execute various controls.

[0014] The engine 1 is, for example, an internal combustion engine that obtains power (mechanical energy) by burning fuel such as a gasoline engine or a diesel engine. The engine 1 is configured such that the adjustment of the output and the operating states such as starting and stopping are electrically controlled. For example, the opening degree of the throttle valve, the supply amount or injection amount of fuel, the injection timing of fuel, the execution and stop of ignition, and the ignition timing are electrically controlled.

[0015] The motor 2 is connected to the crankshaft 1a of the engine 1 so as to be capable of power transmission. Therefore, the motor 2 is driven by the output torque of the engine 1 and is configured to be able to regenerate and generate electricity. In the example shown in FIG. 1, the motor 2 is a so-called motor generator used in the above-described mild hybrid system or a 48V hybrid system, and functions as a starter motor for cranking the engine 1, an assist motor for assisting the output of the engine 1, and a generator (generator or alternator). Further, in the example shown in FIG. 1, the motor 2 transmits the torque output by the motor 2 to the engine 1 via the belt transmission mechanism 7 to crank the engine 1.

[0016] The drive battery 3 corresponds to the "battery" in the embodiment of the present invention and is electrically connected to the motor 2 so as to be able to exchange electric power with the motor 2. The drive battery 3 is, for example, a secondary battery composed of a lithium-ion battery with a rated voltage of 48V, etc., and supplies electric power to the motor 2 when the vehicle Ve starts or accelerates. Then, the torque output by the motor 2 assists the driving force of the vehicle Ve. Further, the drive battery 3 is charged by the electric power generated by the motor 2 when the vehicle Ve decelerates. Also, in the example shown in FIG. 1, the electric power generated by the motor 2 is converted in voltage by a DC-DC converter (DC / DC) 8 and charges, for example, an accessory battery (12V·Battery) 9 with a rated voltage of 12V.

[0017] The accessory battery 9 is a secondary battery such as a lead-acid battery that has been conventionally and generally used, and supplies electric power to a starter motor (Starter) 10, accessories 11, etc. The starter motor 12 is a motor for starting an engine that has been conventionally and generally used, and is driven by the electric power supplied from the accessory battery 9 to crank the engine 1.

[0018] The automatic transmission 4 is connected to the output side of the engine 1 via, for example, a torque converter (not shown). The automatic transmission 4 changes the rotational speed of the engine 1 and transmits the torque output by the engine 1 to drive wheels (not shown) via a drive shaft (not shown) or the like. The automatic transmission 4 is a conventionally generally used transmission for vehicles, and is, for example, a stepped (multi-speed) automatic transmission that controls the power transmission state between a plurality of planetary gear mechanisms (not shown). Alternatively, it may be a transmission of another type such as a belt-type continuously variable transmission or a dual clutch transmission.

[0019] In the vehicle Ve equipped with a 48V mild hybrid system as in the example shown in FIG. 1, basically, normal driving by the output of only the motor 2 is not assumed. However, for example, at the start of the vehicle Ve or during extremely low-speed driving, so-called creep driving or driving at an extremely low speed with a low load by the output of only the motor 2 is possible. Further, the vehicle Ve in the embodiment of the present invention is not limited to the vehicle Ve having the configuration as in the example shown in FIG. 1, and may be a hybrid vehicle having other configurations including the engine 1 and the motor 2 (motor generator) connected to the crankshaft 1a of the engine 1 so as to be capable of power transmission.

[0020] The detection unit 5 is a device or apparatus for acquiring various types of data and information necessary for controlling the vehicle Ve. For example, it includes a power supply unit, a microcomputer, sensors, and input / output interfaces, etc. In particular, the detection unit 5 in the embodiment of this invention detects data for controlling the engine 1, the motor 2, and the drive battery 3 respectively. For example, the detection unit 5 has an engine speed sensor 5a for detecting the rotational speed of the engine 1, a motor speed sensor 5b for detecting the rotational speed of the motor 2, a battery current sensor 5c for detecting the current value of the drive battery 3, an SOC sensor 5d for detecting the state of charge (SOC) of the drive battery 3, a battery temperature sensor 5e for detecting the temperature of the drive battery 3, and various sensors and measuring devices such as a timer 5f for measuring the elapsed time of the control content, etc. And the detection unit 5 is electrically connected to the controller 6 described later, and outputs an electrical signal corresponding to the detection values or calculated values of the various sensors, devices, and apparatuses as described above to the controller 6 as detection data.

[0021] The controller 6 is an electronic control device mainly composed of, for example, a microcomputer, and mainly controls the operations of the engine 1, the motor 2, and the drive battery 3 respectively. Various types of data detected or calculated by the above-described detection unit 5 are input to the controller 6. The controller 6 performs calculations using the input various types of data and the data and calculation formulas stored in advance. And the controller 6 outputs the calculation result as a control command signal, and is configured to control the operations of the engine 1 and the motor 2 as described above respectively. In particular, the controller 6 in the embodiment of this invention executes, for example, idling stop control. The idling stop control performs automatic stop and restart of the engine 1 when a predetermined automatic stop condition is satisfied.

[0022] Further, the controller 6 controls the vehicle Ve as described above and executes battery protection control. The battery protection control is control for preventing the drive battery 3 from exceeding its power limit and protecting the drive battery 3. When executing the above-described idling stop control, the battery protection control first determines, at least based on the temperature of the drive battery 3, whether the power required until the end of the idling stop control, that is, the restart power, can be secured by the drive battery 3. When it is determined that the restart power cannot be secured by the drive battery 3, the execution of the idling stop control is prohibited to prevent the drive battery 3 from exceeding its power limit.

[0023] For example, as shown in FIG. 3, the controller 6 includes a battery control unit 6a and a travel control unit 6b. The battery control unit 6a determines whether the restart power in the above-described idling stop control can be secured by the drive battery 3. Then, the determination result is transmitted to the travel control unit 6b as "ON" or "OFF" of a "protection control intervention prediction flag" based on the battery temperature. The travel control unit 6b determines whether to execute the idling stop control based on "ON" or "OFF" of the "protection control intervention prediction flag". When the "protection control intervention prediction flag" is "OFF", the execution of the idling stop control is permitted, and when the "protection control intervention prediction flag" is "ON", the execution of the idling stop control is prohibited.

[0024] In FIGS. 1 and 3 described above, only one controller 6 is illustrated, but a plurality of controllers 6 may be provided for each device or equipment to be controlled or for each control content.

[0025] As described above, the vehicle control device according to the embodiment of the present invention is configured for the purpose of preventing the drive battery 3 from exceeding its power limit and appropriately protecting the drive battery 3 for a vehicle Ve that performs idling stop control. For this purpose, an example of the control executed by the controller 6 is shown in the flowchart of FIG. 4.

[0026] In the flowchart of FIG. 4, first, in step S1, a pre-notification of the start of idling stop control (S&S) is output. For example, when the start condition of the idling stop control is satisfied, a pre-notification of the start of the idling stop control is transmitted from the traveling control unit 6b to the battery control unit 6a in advance. Note that the control after this step S1 is executed at a timing before the time t1 shown in the time chart of FIG. 2 described above. That is, it is executed before the execution of the idling stop control is started.

[0027] Next, in step S2, a control intervention prediction is performed based on the protection control evaluation value based on the current battery temperature and the battery temperature. Specifically, based on the temperature of the drive battery 3, when the above-described idling stop control is executed, the restart power required until the end of the idling stop control is calculated.

[0028] Then, in step S3, it is determined whether or not the "protection control intervention prediction flag" based on the current battery temperature is "ON".

[0029] If it is determined that the "protection control intervention prediction flag" is "OFF", that is, the restart power for executing the idling stop control can be supplied from the drive battery 3, in this step S3, if it is determined "No", the process proceeds to step S4, and the execution of the idling stop control (S&S) is permitted. Then, thereafter, the routine shown in the flowchart of FIG. 4 is once terminated.

[0030] On the other hand, if it is determined that "Yes" in step S3 because the "protection control intervention prediction flag" is "ON", that is, the restart power for executing the idling stop control cannot be supplied from the driving battery 3, the process proceeds to step S5, and the execution of the idling stop control (S&S) is prohibited. Thereby, an excess of the power limit of the driving battery 3 is prevented. Then, thereafter, the routine shown in the flowchart of FIG. 4 is once terminated.

[0031] As described above, in the vehicle control device according to the embodiment of the present invention, for a vehicle behavior where feedback is not in time, such as when the engine 1 is restarted in the idling stop control, the driving battery 3 that supplies power to the motor 2 to be operated when the engine 1 is restarted is controlled in a feed-forward manner. Thereby, the driving battery 3 can be used appropriately and safely without exceeding the power limit of the driving battery 3. Further, it is possible to prevent the failure of the idling stop control due to an excess of the power limit of the driving battery 3.

[0032] Therefore, according to the vehicle control device in the embodiment of the present invention, for a vehicle Ve that performs idling stop, it is possible to prevent an excess of the power limit of the driving battery 3 and appropriately protect the driving battery 3.

Explanation of Signs

[0033] 1 Engine (ENG) 1a Crankshaft (of the engine) 2 Motor (MG) 3 Driving battery (48V·Battery) 4 Automatic transmission (T / M) 5 Detection unit 5a Engine speed sensor (of the detection unit) 5b Motor speed sensor (of the detection unit) 5c Battery current sensor (of the detection unit) 5d SOC sensor (of the detection unit) 5e Battery temperature sensor (of the detection unit) 5f Timer (of the detection unit) 6 Controller (ECU) 6a Battery control unit (of the controller) 6b Travel control unit (of the controller) 7 Belt transmission mechanism 8 DC-DC converter (DC / DC) 9 Auxiliary battery (12V·Battery) 10 Starter motor (Starter) 11 Accessories Ve Vehicle

Claims

【Claim 1】 A vehicle control device that includes an engine, a motor connected to the crankshaft of the engine and capable of driving the crankshaft when starting the engine, and a battery capable of supplying and receiving electric power to and from the motor, and performs idling stop control for automatically stopping and restarting the engine, the vehicle control device includes a controller that controls the engine, the motor, and the battery and executes the idling stop control when a predetermined automatic stop condition is satisfied, wherein the automatic stop condition includes that the restart power required until the restart is completed in the idling stop control can be supplied from the battery, the controller calculates the restart power based on at least the temperature of the battery, and determines whether the calculated restart power can be supplied from the battery, and prohibits execution of the idling stop control when it is determined that the restart power cannot be supplied from the battery A vehicle control device characterized by the above.

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