JP2015120462A - Device for controlling vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for controlling a vehicle that suppresses or avoids erroneous determination of a failure on a negative terminal side of an on-board battery.SOLUTION: The device for controlling a vehicle is configured to determine generation of a failure on the negative terminal side of the on-board battery when a level of a current flowing into the on-board battery or flowing out from the on-board battery is 0 or less than a predetermined value close to 0 and a fluctuation amount of a voltage of the on-board battery exceeds a determination threshold.

Description

  The present invention relates to a vehicle control device capable of detecting an abnormality on a negative terminal side of a battery mounted on a vehicle.

  Electric power is supplied from an in-vehicle battery to various electrical components mounted on the vehicle and an electric motor that performs cranking when the internal combustion engine is started. The battery is charged by a generator that generates power upon receiving a rotational driving force from the internal combustion engine.

  The in-vehicle battery is subject to vibrations and shocks of the vehicle that is running. As a result, an abnormality may occur in which the wire harness is disconnected from the battery terminal, the wire harness connected to the battery terminal is disconnected, or the battery terminal (terminal) itself is broken.

  If the above-described situation occurs during traveling, the power from the battery is not properly supplied to each part. In this case, the electric power generated by the generator is supplied to the necessary place, and it is possible to continue traveling.

  However, once the internal combustion engine stops, it cannot be restarted. In detail, when a vehicle adopts an idling stop system that improves the fuel efficiency by stopping idle rotation of the internal combustion engine when the vehicle is temporarily stopped, such as waiting for a signal, when an abnormality occurs on the negative terminal side of the battery, Once idling is stopped, electric power is not supplied from the in-vehicle battery to the electric motor that performs cranking at the time of start-up, so that restart cannot be performed.

  In order to cope with such a situation, the terminal voltage of the battery is detected, and abnormality such as disconnection of the battery terminal is detected based on the voltage drop on the plus terminal side (for example, Patent Document 1 below). See).

JP-A-6-189467

  In the above system, it is difficult to detect an abnormality on the negative terminal side of the battery. This is because when the abnormality on the negative terminal side of the battery occurs, the degree of decrease in the voltage on the positive terminal side is small.

  Therefore, the present inventors tried to detect an abnormality on the negative terminal side of the battery by using a current value detected by a current sensor which is arranged in the vicinity of the battery and measures a current flowing into and out of the battery. It was. However, when there is no or almost no current flowing into or out of the battery other than when an abnormality occurs on the negative terminal side of the battery, specifically, the battery is fully charged / full charged. Even when the load is relatively low, the battery power consumption is low, or when the amount of power flowing into the battery due to power generation by the generator is equal to the amount of power flowing out of the battery due to the load, etc. The current is 0 or less than a predetermined value close to 0. Therefore, there is a situation that it is difficult to distinguish between these states and a case where an abnormality occurs on the negative terminal side of the battery.

  When the current value detected by the current sensor is 0 or less than a predetermined value close to 0, if it is determined that an abnormality has occurred on the negative terminal side of the battery, an erroneous determination is made even though no abnormality has occurred. There is a possibility that. In this case, for example, a situation in which idle stop is illegally prohibited due to an erroneous determination occurs.

  The present invention is aimed at suppressing or avoiding erroneous determination of abnormality on the negative terminal side of an in-vehicle battery, paying attention to the above points.

  The present invention employs the following configuration in order to solve the above-described problems. That is, in the present invention, the magnitude of the current flowing into or out of the in-vehicle battery is 0 or less than a predetermined value close to 0, and the amount of fluctuation of the in-vehicle battery voltage exceeds the determination threshold. The vehicle control device that determines that an abnormality has occurred on the negative terminal side of the in-vehicle battery is configured.

  According to the present invention, it is possible to suppress or avoid erroneous determination of abnormality on the minus terminal side of an in-vehicle battery.

The figure which shows schematic structure of the internal combustion engine in one Embodiment of this invention. The circuit diagram of the electrical system in the same embodiment. The graph which shows the value of the current sensor in the same embodiment, and the value of battery voltage.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an outline of an internal combustion engine for a vehicle in the present embodiment. The internal combustion engine in the present embodiment is a spark ignition gasoline engine and includes a plurality of cylinders 1 (one of which is shown in FIG. 1). In the vicinity of the intake port of each cylinder 1, an injector 11 for injecting fuel is provided. A spark plug 12 is attached to the ceiling of the combustion chamber of each cylinder 1. The spark plug 12 receives spark voltage generated by the ignition coil and causes spark discharge between the center electrode and the ground electrode.

  The intake passage 3 for supplying intake air takes in air from the outside and guides it to the intake port of each cylinder 1. On the intake passage 3, an air cleaner 31, an electronic throttle valve 32, a surge tank 33, and an intake manifold 34 are arranged in this order from the upstream.

  The exhaust passage 4 for discharging the exhaust guides the exhaust generated as a result of burning the fuel in the cylinder 1 from the exhaust port of each cylinder 1 to the outside. An exhaust manifold 42 and an exhaust purification three-way catalyst 41 are disposed on the exhaust passage 4.

  As schematically shown in FIG. 2, a cranking motor 61 and a plurality of loads 64 and 69 for starting the internal combustion engine are mounted on the vehicle. Specific examples of the electric loads 64 and 69 include a magnet clutch interposed between the crankshaft of the internal combustion engine and the compressor for compressing the refrigerant of the air conditioner, an air blower for the air conditioner, and a defogger for removing fog from the rear glass. Examples include audio equipment, car navigation systems, illumination lamps (head lamps, tail lamps, fog lamps, blinkers (turn signal lamps), etc.), radiator fans that cool cooling water, and electric power steering devices.

  An alternator 63, which is a source of power supply to the electric loads 64 and 69, is driven to rotate by receiving a driving force transmitted from the crankshaft of the internal combustion engine to generate electric power. The alternator 63 is connected to the crankshaft via a winding transmission mechanism having a belt and a pulley as elements. The magnitude of the voltage generated and output by the alternator 63 can be controlled via the regulator 65. The regulator 65 is a known IC type attached to the alternator 63 and performs a switching operation for switching ON / OFF the energization of the field coil of the alternator 63.

  The output voltage of the alternator 63, that is, the voltage induced in the stator coil of the alternator 63 increases in proportion to fDUTY, which is the DUTY ratio of the field current flowing through the field coil. The regulator 65 receives a signal r for instructing the output voltage of the alternator 63 from an engine control ECU 0 that is one of ECUs (Electronic Control Units), and performs PWM control for adjusting fDUTY so as to realize the instructed output voltage. Do. With this PWM control, the power generated by the alternator 63 can be increased or decreased. The amount of power generated by the alternator 63, in other words, the amount of charge to the battery 62 and / or the amount of power supplied to the electrical loads 64, 69 increases as fDUTY increases and decreases as fDUTY decreases.

  In the regulator 65 of the vehicular alternator 63 that is widely used, the output voltage of the alternator 63 can be switched to two stages, for example, 14.5V or 12.8V. In this case, the engine control ECU 0 inputs to the regulator 65 a signal r that instructs whether the output voltage of the alternator 63 is HI potential = 14.5V or LO potential = 12.8V.

  As the regulator 65, a linear regulator capable of continuously changing the output voltage of the alternator 63 within a predetermined range, for example, between 12V and 15.5V may be employed. In this case, the engine control ECU 0 inputs a signal r that instructs the regulator 65 to set the output voltage of the alternator 63 to any value within the range.

  The LO potential or the minimum output voltage of the alternator 63 is preferably set to a low voltage that is equal to or lower than the normal voltage of the battery 62 or close to that voltage. The potential of the battery terminal (hereinafter referred to as “battery voltage”) increases or decreases depending on the state of charge of the battery 62 or the like, but is usually a predetermined voltage, for example, 12 V or more.

  The alternator 63 becomes a mechanical load when viewed from the internal combustion engine. When the output voltage of the alternator 63 exceeds the battery voltage of the battery 62, the battery 62 is charged and electric power is supplied from the alternator 63 to the electric loads 64 and 69. That is, the alternator 63 performs the work of generating electric energy by consuming energy of rotation of the crankshaft. The amount of charge to the battery 62 and the amount of power supplied to the electric loads 64 and 69 depend on the potential difference between the output voltage of the alternator 63 and the battery voltage.

  Conversely, when the output voltage of the alternator 63 is less than or close to the battery voltage, the battery 62 is not charged, and no power is supplied from the alternator 63 to the electric loads 64 and 69 (the electric load from the battery 62). 64, 69 may be powered). That is, the alternator 63 does not perform work that consumes the energy of rotation of the crankshaft, or the work is reduced.

  In short, when a high output voltage is commanded from the engine control ECU 0 to the regulator 65, the mechanical load of the alternator 63 with respect to engine rotation increases, and when a low output voltage is commanded, the mechanical load of the alternator 63 with respect to engine rotation decreases.

  As described above, the battery 62 is charged by receiving supply of electric power generated by the alternator 63. On the other hand, the battery 62 supplies power to a cranking motor (starter) 61 and various electric loads 64 and 69 for starting the internal combustion engine. The negative terminal side of the battery 62 is grounded.

  In order to prevent a shortage of the amount of power stored in the battery 62 and to avoid overcharging the battery 62, the charging current flowing into the battery 62 and the discharging current flowing out from the battery 62 are constantly monitored, and the balance between charging and discharging. Need to figure out. Therefore, in this embodiment, the battery current sensor 66 for measuring the current flowing into and out of the battery 62 is provided.

  The ECU 0 is a microcomputer system having a processor, a memory, an input interface, an output interface, and the like.

  The input interface of the engine control ECU 0 includes a vehicle speed signal a output from a vehicle speed sensor that detects the actual vehicle speed of the vehicle, a crank angle signal b output from an engine rotation sensor that detects the rotation angle of the crankshaft and the engine speed, Accelerator opening signal c output from a sensor that detects the amount of depression of the accelerator pedal or the opening of the throttle valve 32 as an accelerator opening (engine output required by the driver, so-called required load), and the range of the shift lever are known. Intake temperature / intake pressure output from a temperature / pressure sensor for detecting the shift range signal d output from the sensor (shift position switch) for detecting the intake air temperature and the intake pressure in the intake passage 3 (particularly, the surge tank 33). Cooling output from a water temperature sensor that detects a cooling water temperature indicating the signal e, the temperature of the internal combustion engine The temperature signal f, the cam angle signal g output from the cam angle sensor at the plurality of cam angles of the intake camshaft or the exhaust camshaft, the battery current signal h output from the battery current sensor 66, and the alternator 63 generate and output. A power generation amount signal s output from a sensor that detects a voltage or current that is detected, a battery voltage signal t that indicates a battery voltage, and the like are input.

  From the output interface, an ignition signal i for the igniter of the spark plug 12, a fuel injection signal j for the injector 11, an opening operation signal k for the throttle valve 32, and a switch on the electric circuit for energizing the magnet clutch. On the other hand, a clutch engagement signal o, a switch ON signal p for a switch on an electric circuit energizing motors, heaters and other electric loads 64 and 69, and a voltage instruction for a voltage regulator 65 which controls a voltage generated by the alternator 63 The signal r and the like are output.

  The processor of the engine control ECU 0 interprets and executes a program stored in advance in the memory, calculates operation parameters, and controls the operation of the internal combustion engine. The ECU 0 obtains various information a, b, c, d, e, f, g, h, s, and t necessary for operation control of the internal combustion engine via the input interface, and knows the engine speed and also uses the cylinder 1 Estimate the amount of intake air to be filled. Based on the engine speed, the intake air amount, and the like, various operating parameters such as required fuel injection amount, fuel injection timing (including the number of times of fuel injection for one combustion), fuel injection pressure, and ignition timing are determined. As the operation parameter determination method itself, a known method can be adopted. The engine control ECU 0 applies various control signals i, j, k, o, p, r corresponding to the operation parameters via the output interface.

  In the present embodiment, the engine control ECU 0 communicates with other ECUs such as an ABS control ECU, an auto air conditioner ECU, a CVT control ECU, and an idle stop control ECU, as a communication bus represented by a CAN (Controller Area Network) or a dedicated line. Send and receive information to and from each other. That is, each ECU shares control data such as sensor output values necessary for control with other ECUs.

  The ABS control ECU acquires vehicle speed information from the vehicle speed sensor, and acquires information on the master cylinder pressure (M / C pressure) of the brake mechanism from the hydraulic pressure sensor.

  The idle stop control ECU receives information related to the operation of the internal combustion engine such as the engine speed, the coolant temperature, the negative pressure, and the throttle opening from the engine control ECU 0. Information such as vehicle speed and master cylinder pressure is received from the ABS control ECU, and information such as the presence or absence of lockup by the lockup clutch is received from the CVT control ECU.

  The auto air conditioner ECU receives information such as the outside air temperature and outputs a command signal to an air conditioner, a defogger, and the like.

  Furthermore, the engine control ECU 0 and the positive terminal of the battery 62 are connected. Thus, the battery voltage signal t is input to the engine control ECU 0, and the battery voltage can be monitored by the engine control ECU 0.

  The engine control ECU 0 of the present embodiment executes an idle stop that stops the idle rotation of the internal combustion engine when the vehicle stops due to a signal waiting or the like. The engine control ECU 0 determines that the vehicle speed is not more than a predetermined value (for example, a value of 9 km / h to 13 km / h), the shift position is the travel range (in the case of an AT vehicle), the brake pedal is depressed, and the master cylinder pressure is The idling stop condition is satisfied when the vehicle battery voltage is equal to or higher than a predetermined value (for example, 0.7 MPa) and the conditions such as the internal combustion engine cooling water temperature is higher than a predetermined value are all satisfied. Judge that it was done.

  When a predetermined idle stop end condition is satisfied after the idle stop condition is satisfied, the internal combustion engine is restarted. The engine control ECU 0 has changed the shift position to the non-traveling range (for AT cars), the brake pedal depression has been loosened, and the master cylinder pressure has fallen below the threshold, and the driver has released his foot from the brake pedal On the contrary, when the brake pedal is further depressed, the accelerator pedal is depressed, or a predetermined time (for example, 3 minutes) has elapsed in the idle stop state, the idle stop termination condition is satisfied. Judge.

  When a restart request is generated during idle stop, the starter motor pinion gear is engaged with the ring gear on the outer periphery of the flywheel (in the case of MT vehicle) or the drive plate (in the case of AT vehicle) and cranking is performed. Then, the fuel injection (and ignition) from the injector in the internal combustion engine is restarted, and the internal combustion engine is restarted.

Hereinafter, a method for detecting whether or not an abnormality has occurred on the negative terminal side of the in-vehicle battery 62 will be described in detail. Here, "There is an abnormality on the negative terminal side"
-The wire harness is disconnected from the negative terminal of the battery 62,
-The wire harness connected to the negative terminal of the battery 62 is disconnected,
-The negative terminal (terminal) of the battery 62 is damaged.
Or it means the situation according to this. In such a case, as indicated by a period T in FIG. 3, the value of the current sensor 66 becomes a substantially constant value near 0, the battery voltage fluctuates greatly, and the behavior becomes unstable. The period T indicates a period in which the above-described abnormality has occurred on the negative terminal side and the negative terminal side of the in-vehicle battery 62 is not grounded.

  Thus, the ECU 0 as the control device of the present embodiment has a magnitude of the current flowing into or out of the in-vehicle battery 62 being 0 or less than a predetermined value close to 0 (almost 0), and When the fluctuation amount of the voltage of the in-vehicle battery 62 exceeds the determination threshold, it is determined that an abnormality has occurred on the minus terminal side of the in-vehicle battery 62.

  Specifically, first, during traveling of the vehicle, the ECU 0 determines whether or not the value of the current sensor 66 is 0 or less than a predetermined value close to 0. This is because, when an abnormality occurs on the negative terminal side of the battery 62, no current flows through the current sensor 66 or almost no current flows.

If the value of the current sensor 66 is 0 or less than a predetermined value close to 0, it is next determined whether or not the battery voltage fluctuation amount exceeds a determination threshold value. In particular,
Within a predetermined period, the difference between the battery voltage and a predetermined value (for example, a constant such as 14 V corresponding to the full charge of the battery 62 or an average value of the battery voltage for a certain period in the past) exceeds the determination threshold. Based on the accumulated number of times
・ Compare the difference between the maximum value (or maximum value) and minimum value (or minimum value) of the battery voltage within the specified period (or its integrated value) and the judgment threshold,
・ Comparison of the battery voltage distribution for a predetermined period (how much the battery voltage is dispersed from the average value of the battery voltage for a certain period in the past) and the determination threshold value, or
A determination is made by comparing a period in which the difference between the maximum value (or maximum value) and the minimum value (or minimum value) of the battery voltage is a certain value or more and a predetermined period that is a determination threshold value. The comparison between the variation amount of the battery voltage and the determination threshold value is not limited to that described above, and various changes can be made.

  Therefore, when the fluctuation amount of the battery voltage exceeds the determination threshold, it can be determined that an abnormality has occurred on the negative terminal side of the battery 62. That is, if an abnormality occurs on the negative terminal side of the battery 62, the negative terminal side is not grounded, and the S / N ratio (signal-to-noise ratio) is lowered, resulting in an unstable battery voltage.

  When it is determined that an abnormality has occurred on the negative terminal side of the battery 62, control for prohibiting idle stop can be performed to avoid a situation in which the internal combustion engine cannot be restarted after being temporarily stopped. Therefore, it becomes possible to continue driving the vehicle for a certain period even in a situation where the function of the battery is lowered. The driver can evacuate to a place where the vehicle can be repaired (such as a dealer) or a safe place (such as an emergency parking zone on a highway) during that period.

  Moreover, you may control so that the electrical load unnecessary for evacuation driving | running | working may be reduced. Furthermore, the battery 62 may be output in a manner that appeals to the driver's vision and / or hearing that an abnormality has occurred (for example, a lamp is lit or an alarm sound is emitted).

  In the present embodiment, the magnitude of the current flowing into or out of the in-vehicle battery 62 is 0 or less than a predetermined value close to 0, and the variation amount of the voltage of the in-vehicle battery 62 is the determination threshold value. The vehicle control device 0 that determines that an abnormality has occurred on the negative terminal side (that is, the grounding side) of the on-vehicle battery 62 when the value exceeds the value is configured.

  With such a configuration, it is possible to suppress or avoid erroneous determination regarding abnormality of the negative terminal of the in-vehicle battery 62 that occurs during operation of the internal combustion engine. That is, since the determination is made by referring to the amount of fluctuation in the voltage of the in-vehicle battery 62 in addition to the magnitude of the current in the in-vehicle battery 62, voltage fluctuation due to an abnormality on the negative terminal side of the battery 62 or voltage due to other factors It is possible to determine whether it is a fluctuation, and it is possible to suppress erroneous determination as in the past.

  In particular, in the case of a vehicle that employs an idle stop system as in the present embodiment, when it is erroneously determined that the vehicle-mounted battery 62 is normal but is abnormal, a control that illegally prohibits idle stop. There can be a situation where this happens. However, if the control device 0 is provided as in the present embodiment, erroneous determination is eliminated, and if there is an idle stop request in such a case, the idle stop can be performed. Therefore, fuel consumption performance can be improved.

  On the contrary, since it is not erroneously determined that the vehicle-mounted battery 62 is normal even though there is an abnormality, it avoids a situation where the engine stops idling even though the restart is impossible. be able to.

  Furthermore, since it is not necessary to use a special disconnection detection circuit or sensor in order to perform such an abnormality detection, a known system can be used and the cost can be reduced.

  The present invention is not limited to the embodiment described in detail above.

  Battery voltage is not always measured directly. For example, instead of directly measuring the battery voltage, when using an alternator with a regulator that can control the battery voltage to the target value, the battery voltage can be adjusted by the engine control ECU. The target value of the battery voltage commanded from the engine control ECU to the IC regulator can be regarded as the current battery voltage. That is, the engine control ECU always knows the battery voltage.

  Further, the battery current value is not always directly measured. For example, an estimated value obtained from the battery voltage and resistance may be used instead of the actual measurement value obtained by directly measuring the battery current using the current sensor. As an example, the estimated value of the battery current includes the battery voltage, the voltage in the relay box (node) arranged downstream of the battery, and the resistance value of the wire harness connecting the battery and the relay box (node). Can be used to calculate. The control unit for obtaining the potential of the nodal point is an ECU for controlling the load and mechanism of each unit mounted on the vehicle, and the load or mechanism controlled by this ECU is not operating. As long as a large current does not flow through the ECU, any ECU may be used. For example, an ABS control ECU, a steering lock ECU, an auto air conditioner ECU, or the like can be used. When a large current does not flow through the ABS control ECU, steering lock ECU, and auto air conditioner ECU, the applied voltage (inter-terminal voltage) of the ECU is considered to be substantially the same as the voltage in the relay box, which is the potential of the node. Because it can. Therefore, what is necessary is just to make it the application voltage of the said ECU input into engine control ECU using CAN communication.

  In addition, the specific configuration of each unit and the specific processing procedure can be variously modified without departing from the spirit of the present invention.

  The present invention can be used for an internal combustion engine mounted on a vehicle or the like.

0 ... Control unit (ECU)
62 ... Battery

Claims (1)

When the magnitude of the current flowing into or out of the in-vehicle battery is 0 or less than a predetermined value close to 0 and the voltage fluctuation amount of the in-vehicle battery exceeds the determination threshold, the in-vehicle battery A vehicle control device that determines that an abnormality has occurred on the negative terminal side of the vehicle.

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