JP6562604B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control apparatus including an internal combustion engine and a generator.

  In a vehicle equipped with an internal combustion engine, it is usual to operate a generator by a driving force output from the internal combustion engine and supply electric power generated by the generator to an electrical system of the vehicle (for example, see Patent Document 1 below). ).

  When the electrical load increases, for example, when an illumination light such as a headlamp is turned on, an electric fan is started, or an air conditioner starts operation, the power supply is increased due to an increase in power consumption. The terminal voltage (particularly, battery voltage) of the power storage device (battery or capacitor) is reduced. On the other hand, the controller or regulator attached to the generator performs control to increase the amount of power generated by the generator so as to maintain the terminal voltage of the power storage device or the output voltage of the generator at a given target voltage.

  If the increase in the amount of power generated by the generator, in other words, the increase in the excitation current flowing through the coil of the generator is steep, the mechanical load of the generator on the internal combustion engine increases rapidly, and the engine rotation becomes unstable. Therefore, a known generator controller or regulator has a so-called gradual excitation function that gradually increases the excitation current with respect to an increase in the electrical load.

JP 2014-101847 A

  Conventionally, the rate of increase of the excitation current due to gradual excitation has been uniquely determined by the specifications of the controller or regulator. For this reason, when the internal combustion engine is idling or operating at a low load close to idling, the amount of power generated by the generator rapidly increases and the load temporarily concentrates on the internal combustion engine, causing an undesirable decrease in engine speed. There are still concerns that cause hunting and hunting.

  Of course, it is also conceivable to preliminarily design the increase rate of the excitation current in the gradual excitation function of the controller or regulator of the generator with emphasis on the idling or low-load operation stability of the internal combustion engine. However, in a medium to high load or medium to high rotation operation region where there is little risk of engine stall, the increase in the amount of power generation is delayed with respect to the increase in electric load, and the power storage device (lead battery, etc.) It can lead to other types of problems, such as shortening the service life and destabilization of the electrical system.

  An object of the present invention, which has been made paying attention to the above points, is to appropriately suppress instability of engine rotation accompanying an increase in the amount of power generated by a generator.

  In order to achieve such an object, the present invention takes the following measures.

That is, the vehicle control device according to the present invention is a vehicle control device equipped with an internal combustion engine and a generator that is driven by the internal combustion engine to generate electric power, and is an allowable upper limit value of an excitation current flowing through a coil of the generator. Can be commanded to the generator, and in a situation where the amount of power generated by the generator increases, a constant upper limit value for the excitation current can be commanded to the generator, or a gradually increasing upper limit value can be generated. When commanding an upper limit value that gradually increases to the generator, the increment of the upper limit value per unit time is set as the fuel cut. The inside is smaller than the rate of increase of the excitation current by the gradual excitation function during normal times, and is smaller than during fuel cut during idle or low load operation.

  If this is the case, the increase in the output of the internal combustion engine is not in time for the increase in the mechanical load caused by the generator, effectively avoiding the problem of unnecessary decrease in engine speed and hunting. be able to. In other words, it is possible to appropriately suppress instability of engine rotation accompanying an increase in the amount of power generated by the generator. As a result, it is possible to achieve both stable driving of the internal combustion engine and high charging efficiency of the generator.

  According to the present invention, a vehicle capable of achieving both stable driving of an internal combustion engine and high charging efficiency of a generator by appropriately suppressing instability of engine rotation accompanying an increase in the amount of power generated by the generator. A control device can be provided.

The figure which shows schematic structure of the internal combustion engine in one Embodiment of this invention. The figure which shows typically the aspect of the connection of the internal combustion engine and ISG in the embodiment. The figure which shows the electric circuit for controlling the various electric loads mounted in the vehicle. The figure which shows the electric circuit of ISG in the embodiment. The figure which shows schematic structure of the drive system in one Embodiment of this invention. The figure which shows typically the value of the exciting current in the same embodiment, and its upper limit. The timing chart in the same embodiment.

  An embodiment of the present invention will be described with reference to the drawings. A vehicle internal combustion engine 100 shown in FIG. 1 is a spark ignition type four-stroke 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.

  An external EGR (Exhaust Gas Recirculation) device 2 realizes a so-called high-pressure loop EGR. The EGR device 2 includes an external EGR passage 21 that communicates the upstream side of the catalyst 41 in the exhaust passage 4 and the downstream side of the throttle valve 32 in the intake passage 3, an EGR cooler 22 provided on the EGR passage 21, and an EGR passage 21. And an EGR valve 23 that controls the flow rate of the EGR gas flowing through the EGR passage 21. The inlet of the EGR passage 21 is connected to the exhaust manifold 42 in the exhaust passage 4 or a predetermined location downstream thereof. The outlet of the EGR passage 21 is connected to a predetermined location downstream of the throttle valve 32 in the intake passage 3, specifically to a surge tank 33.

  As shown in FIG. 2, the internal combustion engine 100 according to the present embodiment is accompanied by a starter motor (cell motor) 140, an ISG (Integrated Starter Generator), a compressor 130, and other auxiliary machines.

  The starter motor 140 is an electric motor dedicated to cranking that mainly drives the crankshaft 10 of the internal combustion engine 100 during cold start. The starter motor 140 has a pinion gear 141 on its output shaft, and the pinion gear 141 rotates on the crankshaft 10 by meshing with a ring gear 103 fixed to the crankshaft 10 that is the output shaft of the internal combustion engine 100. Transmits driving force. The pinion gear 141 is detached from the ring gear 103 except when the starter motor 140 is cranking the internal combustion engine 100.

  The ISG 110 has a function as an electric motor that drives the crankshaft 10 and thus the vehicle axle 153 (and driving wheels), and a function as a generator that generates electric power by receiving driving force transmitted from the crankshaft 10. The ISG 110 is connected to one end side of the crankshaft 10 of the internal combustion engine 100 via the winding transmission mechanisms 112, 113, and 101.

  The ISG 110 is, for example, an inner-rotor type AC synchronous machine, and includes a rotor (rotor) having both permanent magnets and a rotor coil (excitation (field) winding) 116, and a three-phase AC facing the outer peripheral surface of the rotor. A stator (stator) including a stator coil (stator winding) 115 is used as an element. The rotor is fixed to the outer periphery of the rotor shaft 111. Pulleys (or sprockets) 112 and 101 are fixed to the rotor shaft 111 and the crankshaft 10, respectively, and the crankshaft 10 and the rotor shaft are secured by a belt (or chain) 113 wound around the pulleys 112 and 101. The rotational driving force is transmitted to and from 111 (bidirectionally).

  The ISG 110 supplies power from the in-vehicle power storage device 61 mainly when the internal combustion engine 100 that has been idle-stopped is restarted or when the traveling drive force supplied to the axle 153 is increased (particularly during acceleration or climbing). In response, the crankshaft 10 is rotationally driven. Power storage device 61 includes a battery and / or a capacitor. In turn, when power is generated by being rotationally driven by the crankshaft 10, the power storage device 61 is charged with the generated power. When the vehicle decelerates, regenerative braking is performed by the ISG 110, and the kinetic energy of the vehicle can be recovered as electric energy.

  The compressor 130 for compressing the refrigerant of the air conditioner is also connected to one end side of the crankshaft 10 of the internal combustion engine 100 via the winding transmission mechanisms 102, 134, 133, similarly to the ISG 110. Pulleys (or sprockets) 133 and 102 are fixed to the input shaft 132 and the crankshaft 10 of the compressor 130, respectively, and the belt (or chain) 134 wound around the pulleys 133 and 102 causes the crankshaft 10 The rotational driving force is transmitted to the input shaft 132. The belt 134 may transmit driving force to a lubricating oil pump (not shown), a cooling water pump (not shown), or the like, which is an auxiliary machine other than the compressor 130. A magnet clutch 131 that can be connected and disconnected is provided between the main body of the compressor 130 and the input shaft 132, and the clutch 131 is disconnected when the air conditioner is not operated.

  A transmission 120, which is a drive system that connects the internal combustion engine 100 and the axle 153, is installed on the other end side of the crankshaft 10.

  Various electric loads are mounted on the vehicle. Specific examples of electrical loads include air conditioner blowers, rear glass defoggers, audio equipment, car navigation systems, lighting (headlamps, taillights, stoplights (brakelights), foglights, turn signals (turns) Signal lamp)), a radiator fan for cooling the cooling water of the internal combustion engine, an electric power steering device, and the like.

  FIG. 3 shows an electric circuit for controlling the electric load. As already described, the magnet clutch 131 is interposed between the crankshaft 10 of the internal combustion engine and the refrigerant compression compressor 130. When operating the air conditioner, the magnet clutch 131 is energized to engage the clutch 131. When the air conditioner is not operated, the magnet clutch 131 is not energized and the clutch 131 is disconnected. Energization and disconnection of the magnet clutch 131 is performed by ON / OFF of the relay switch 62.

  The motor 63 that rotationally drives the blower for blowing and the heating wire heater 65 laid on the rear glass as a defogger operate by receiving power supply from the power storage device 61 (or ISG 110). The energization and interruption of the motor 63 and the heater 65 are performed by turning ON / OFF the relay switch 64 or starting / switching a semiconductor switching element (power device represented by a power transistor, power MOSFET, etc.). Do by arc extinguishing.

  The same applies to audio devices, car navigation systems, illumination lamps, motors that rotate the radiator fan, and other electrical loads.

  FIG. 4 shows an equivalent circuit of the ISG 110 that functions as a generator. When the ISG 110 is operated as a generator, a three-phase AC induced current is generated in the stator coil 115 which is a three-phase coil. This induced current is converted to a direct current by a rectifier 113 using a diode, and then supplied to the power storage device 61 and an electric load.

  A controller 114 attached to the ISG 110 receives a control signal n for instructing a target value of an output voltage of the ISG 110, which is issued from an ECU (Electronic Control Unit) 0 that is a control device of the present embodiment. Then, in order to make the terminal voltage of the power storage device 61 (in other words, the power supply voltage supplied to the electrical system) follow the commanded target voltage, the exciting current applied to the rotor coil 116 by switching the semiconductor switching element 119 PWM (Pulse Width Modulation) control is performed to adjust the size of. The output voltage of the ISG 110, that is, the generated voltage induced in the stator coil 115, increases as the exciting current flowing through the rotor coil 116 increases.

  The ISG 110 that operates as a generator is a mechanical load when viewed from the internal combustion engine 100. When the output voltage of the ISG 110 exceeds the terminal voltage of the power storage device 61, the power storage device 61 is charged and power is supplied from the ISG 110 to the electric load. That is, the ISG 110 spends the energy of rotation of the crankshaft 10 to generate electrical energy. The amount of charge to the power storage device 61 and the amount of power supplied to the electrical load depend on the potential difference between the output voltage of the ISG 110 and the terminal voltage of the power storage device 61.

  Conversely, when the output voltage of ISG 110 is less than or close to the terminal voltage of power storage device 61, power storage device 61 is not charged, and no power is supplied from ISG 110 to the electrical load (power from power storage device 61 to the electrical load). May be supplied). In other words, the ISG 110 does not perform work that consumes the energy of rotation of the crankshaft 10, or the work is reduced.

  In short, when a high power generation voltage is commanded from the ECU 0 to the ISG 110, the mechanical load of the ISG 110 with respect to engine rotation increases, and when a low power generation voltage is commanded, the mechanical load of the ISG 110 with respect to engine rotation decreases.

  Incidentally, the controller 114 has a gradual excitation function that gradually increases the excitation current instead of increasing the excitation current stepwise when increasing the amount of power generated by the ISG 110 in accordance with an increase in the electrical load. This gradual excitation function avoids temporary concentration of the mechanical load on the internal combustion engine 100 and prevents a decrease in engine rotation in an idle operation or low load operation region.

  In addition, the controller 114 receives a control signal n that is issued from the ECU 0 and commands an upper limit value of the excitation current, detects the magnitude of the excitation current flowing through the rotor coil 116 via the sensor 117, and commands the excitation current. Regulated below the specified upper limit. The upper limit of the excitation current is intended to prevent the mechanical rotation on the internal combustion engine 100 from becoming excessive and the engine rotation from becoming unstable. Therefore, for example, when the refrigerant compression compressor 130 is operated and when it is not operated, the upper limit value of the excitation current is lower in the former case.

  Clipping to the upper limit value of the excitation current has priority over following the target voltage value of the generated voltage of the ISG 110. In other words, even if the terminal voltage of the power storage device 61 is still less than the target voltage commanded from the ECU 0, the controller 114, when the excitation current flowing through the rotor coil 116 has already reached the upper limit commanded from the ECU 0, The excitation current is not increased further.

  On the other hand, when the ISG 110 is operated as an electric motor for driving the crankshaft 10, a three-phase alternating current is passed through the inverter 118 using a semiconductor switching element to the stator coil 115 while energizing the rotor coil 116 with a required excitation current. Is applied to generate a rotating magnetic field around the rotor. The high side switch and the low side switch of each phase of the inverter 118 are fired / extinguished by the controller 114.

  FIG. 5 shows an example of a transmission 120 which is a drive system provided in the vehicle. The transmission 120 includes a torque converter 7 and automatic transmissions 8 and 9. In particular, in the present embodiment, a forward / reverse switching device 8 using a planetary gear mechanism and a belt-type CVT (Continuously Variable Transmission) 9 which is a type of continuously variable transmission are adopted as components of the automatic transmissions 8 and 9. doing.

  The rotational torque output from the internal combustion engine is input from the crankshaft of the internal combustion engine to the pump impeller 71 on the input side of the torque converter 7 and transmitted to the turbine runner 72 on the output side. The rotation of the turbine runner 72 is transmitted to the drive shaft 94 of the CVT 9 via the forward / reverse switching device 8 and rotates the driven shaft 95 through a shift in the CVT 9. The rotation of the driven shaft 95 is transmitted to the output gear 151. The output gear 151 meshes with the ring gear 152 of the differential device, and rotates the axle 153 and the drive wheels (not shown) via the differential device.

  The torque converter 7 includes a lockup mechanism. The lock-up mechanism is known in this field, and a lock-up clutch 73 that fastens the input side and the output side of the torque converter 7 so as not to rotate relative to each other, and an operation for switching the connection of the lock-up clutch 73. A lock-up solenoid valve (not shown) for controlling the hydraulic pressure (hydraulic pressure) is used as an element. The lockup solenoid valve is a flow rate control valve that receives a control signal t and changes its opening degree.

  In a vehicle equipped with CVT 9, when the vehicle speed is a predetermined value (for example, 10 km / h) or more, the torque converter 7 is almost always locked up. When the vehicle speed is equal to or lower than the predetermined value, the lockup of the torque converter 7 is released. During lockup, the lockup clutch 73 is pressed against the torque converter cover 74 and rotates together with the torque converter cover 74. The engine torque input to the input side (drive plate) of the torque converter 7 at the time of lock-up is output from the torque converter cover 74 via the lock-up clutch 73 and thus to the forward / reverse switching device 8. Communicated directly to. At the time of lockup, the speed ratio, which is the ratio of the output side rotational speed of the torque converter 7 to the input side rotational speed, is 1.

  In turn, the lock-up clutch 73 is separated from the torque converter cover 74 at the time of non-lock-up. At the time of non-lock-up, the engine torque input to the input side of the torque converter 7 is transmitted from the torque converter cover 74 to the pump impeller 71 and the turbine 72 and is transmitted to the forward / reverse switching device 8. At the time of non-lock-up, the speed ratio of the torque converter 7 becomes smaller or larger than 1 depending on the driving state.

  In the forward / reverse switching device 8, the sun gear 81 communicates with the turbine runner 72, and the ring gear 82 communicates with the drive shaft 94. Between the planetary carrier 83 that supports the planetary gear 831 and the transmission case, a forward brake 84 that is a hydraulic clutch that can be connected and disconnected is interposed. Further, a reverse clutch 85, which is a hydraulic clutch capable of switching connection / disconnection, is also interposed between the planetary carrier 83 and the sun gear 81 (or the output side of the torque converter 7).

  In the D range of the traveling range, the forward brake 84 is engaged and the reverse clutch 85 is disconnected. As a result, the rotation of the output shaft of the torque converter 7 is reversed and decelerated and transmitted to the drive shaft 94 for forward travel. In turn, in the R range, the reverse clutch 85 is engaged and the forward brake 84 is disconnected. As a result, the sun gear 81 and the planetary carrier 83 rotate integrally, and the output shaft of the torque converter 7 and the drive shaft 94 are directly connected to perform reverse travel. A solenoid valve (not shown) that controls the hydraulic pressure for driving the forward brake 84 or the reverse clutch 85 to connect / disconnect is a flow rate control valve that receives a control signal u and changes its opening.

  In the N range and P range, which are non-traveling ranges, both the forward brake 84 and the reverse clutch 85 are disconnected.

  The CVT 9 includes a driving pulley 91 and a driven pulley 92, and a belt 93 wound around the pulleys 91 and 92 as elements. The drive pulley 91 is disposed behind the movable sheave 912, a fixed sheave 911 fixed to the drive shaft 94, a movable sheave 912 supported on the drive shaft 91 via a roller spline so as to be displaceable in the axial direction. A hydraulic servo 913 is provided, and the gear ratio can be changed steplessly by operating the hydraulic servo 913 and displacing the movable sheave 912. The driven pulley 92 is disposed on the back of the movable sheave 922, a fixed sheave 921 fixed to the driven shaft 95, a movable sheave 922 supported on the driven shaft 95 via a roller spline so as to be axially displaceable. A hydraulic servo 923 is provided, and a belt thrust necessary for torque transmission is applied by operating the hydraulic servo 923 and displacing the movable sheave 922.

  A hydraulic pump (hydraulic fluid) supplied to the forward brake 84 or the reverse clutch 85 to operate the travel range, and a hydraulic pump (discharge fluid) supplied to the hydraulic servos 913 and 923 to operate the gear ratio. (Not shown) is a known mechanical type (non-electric type) that operates by receiving torque transmitted from the crankshaft of the internal combustion engine. This hydraulic fluid is common to the fluid used for the torque converter 7.

  The ECU 0 is a microcomputer system having a processor, a memory, an input interface, an output interface, and the like. The input interface 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 10 and the engine speed, and an accelerator pedal. From an accelerator opening signal c output from a sensor that detects the amount of depression of the engine or the opening of the throttle valve 32 as an accelerator opening (in other words, a required load), a sensor (shift position switch) for knowing the range of the shift lever An output shift range signal d, an intake air temperature / intake pressure signal e output from a sensor for detecting intake air temperature and intake air pressure in the intake passage 3 (particularly, the surge tank 33), and a cooling water temperature of the internal combustion engine 100 are detected. The coolant temperature signal f output from the sensor, the brake pedal being depressed, or the brake pedal Output from a sensor that detects a brake signal g output from a sensor (such as a brake switch or a master cylinder pressure sensor) that detects the amount of pedal depression, a terminal voltage and a terminal current (particularly, battery voltage or battery current) of the power storage device 61 The voltage / current signal h, the operation request signal m regarding whether or not to operate the air conditioner and various electric loads, the status signal s provided from the controller 114 of the ISG 110, and the like are input.

  The operation request signal m is manually issued from an operation switch (or control panel) for each air conditioner or electric load, which is manually operated by a driver or passenger who desires to operate the air conditioner and various electric loads. It may be a control signal or an automatic control signal issued from an auto air conditioner ECU that controls the auto air conditioner system.

  The status signal s includes various information related to the ISG 110, such as the rotation speed and temperature, the magnitude of the excitation current flowing through the rotor coil 116, the current operation mode (that is, whether the power generation is being performed, the internal combustion engine 100 is being cranked, Information on whether the internal combustion engine 100 is motor-assisted or in a no-load state in which neither the generator nor the motor works.

  From the output interface of the ECU 0, 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 an opening operation for the EGR valve 23. Signal l, control signal n for controlling the controller 114 of the ISG 110, clutch engagement signal o for the switch 62 on the electric circuit for energizing the magnet clutch 131, the motor 63, the heater 65 and other electric loads Switch ON signals p and q for the switches 64 and 66 on the electric circuit to be energized, the opening control signal t for the lockup solenoid valve for switching the connection and disconnection of the lockup clutch 73, the forward brake 84 or the reverse clutch 85. Opening control signal u for the solenoid valve for switching connection / disconnection of And outputs the transmission ratio control signal v such relative VT9.

  The control signal n is a signal for instructing the operation mode of the ISG 110 and for instructing a target value of the generated voltage to be output from the ISG 110 when operating as a generator, an upper limit value of the excitation current to be supplied to the rotor coil 116, and the like. .

  The processor of the 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 100. The ECU 0 acquires various information a, b, c, d, e, f, g, h, m, and s necessary for operation control of the internal combustion engine 100 via the input interface, and the required throttle valve 32 opening degree. , Required fuel injection amount, fuel injection timing (including the number of times of fuel injection for one combustion), fuel injection pressure, ignition timing, ON / OFF of air conditioner compressor, ON / OFF of various electric loads, ISG110 Various operating parameters such as the power generation amount or output, whether or not to lock up the torque converter 7, and the gear ratio of the automatic transmissions 8 and 9 are determined. The ECU 0 applies various control signals i, j, k, l, n, o, p, q, s, t, u, v corresponding to the operation parameters via the output interface.

  In addition, the ECU 0 inputs the control signal r to the starter motor 140 when the internal combustion engine 100 is started, particularly during cold start, and engages the pinion gear 141 with the ring gear 103 to crank the internal combustion engine 100.

  The ECU 0 executes an idle stop that stops the idle rotation of the internal combustion engine 100 when a predetermined idle stop condition is satisfied. The ECU 0 has a brake pedal depression amount or a master cylinder pressure equal to or higher than a threshold value (the brake pedal is depressed), the cooling water temperature of the internal combustion engine is higher than a predetermined level, the terminal voltage of the power storage device 61 is higher than a predetermined level, and the ISG 110 Is substantially not generating electricity, the magnet clutch 131 is disengaged, the refrigerant compression compressor 130 is not operating, the shift range is the travel range, and the vehicle has accelerated beyond a certain vehicle speed since the end of the previous idle stop. Have a history and the current vehicle speed is below a certain vehicle speed (for example, the vehicle speed has dropped from 13.5 km / h to 13 km / h, or from 9.5 km / h to 7 km / h) It is determined that the idle stop condition is satisfied when all the conditions are satisfied.

  When a predetermined idle stop end condition is satisfied after the idle stop condition is satisfied, the internal combustion engine 100 is restarted. The ECU 0 determines that the brake pedal depression amount or the master cylinder pressure is 0 or less than a threshold value close to 0 (the brake pedal is no longer depressed), and conversely, the brake pedal depression amount or the master cylinder pressure further increases (brake The idle stop termination condition is met when the pedal is depressed more), the accelerator opening is increased (the accelerator pedal is depressed), or the predetermined time (3 minutes) has elapsed in the idle stop state. Judge that it was done. In principle, when restarting after an idle stop, the internal combustion engine 100 is cranked by operating the ISG 110 as an electric motor.

  Further, the internal combustion engine 100 according to the present embodiment performs a fuel cut that interrupts the fuel injection according to the operation state. Normally, when the accelerator pedal depression amount is 0 or less than a threshold value close to 0 and the engine speed is equal to or higher than the fuel cut permission speed, the fuel cut is started assuming that the fuel cut condition is satisfied. Then, when any fuel cut end condition is satisfied, such as when the accelerator pedal depression amount exceeds the threshold value, or the engine speed decreases to the fuel cut return speed, the fuel cut ends and the fuel injection resumes. .

  Therefore, as shown in FIG. 6, the ECU 0 as the vehicle control apparatus according to the present embodiment commands the ISG 110 to set a constant upper limit value x1 for the excitation current in a situation where the amount of power generated by the ISG 110 as the generator increases. Control is executed to select whether to instruct the ISG 110 to the upper limit value x2 that gradually increases or not, depending on the operating state of the internal combustion engine 100.

  Here, “under a situation where the amount of power generation increases” refers in particular to a situation where the electrical load increases (air conditioner is activated, lighting is turned on, fan is activated, etc.). Point to. In other words, “under a situation where the amount of power generation increases” means that the terminal voltage of the power storage device 61 serving as a power source for the electric load temporarily decreases, that is, the terminal voltage and the target voltage (the power generation voltage commanded to the ISG 110). In order to reduce this deviation, the controller 114 of the ISG 110 increases the excitation current to increase the power generation amount.

  In addition, the “operating state of the internal combustion engine 100” for executing the control is at least a low load operation region close to idle operation or idle operation (required load = the amount of depression of the accelerator pedal is 0 or less than a threshold value close to 0, It is classified into three patterns: not in fuel cut), in fuel cut, or other states. In the present embodiment, among the three patterns, the former two patterns will be described later.

  As shown in FIG. 6, the excitation current applied to the ISG 110 behaves like a normal excitation current y1 by a gradual excitation function preset by the controller 114 in the normal operation state. However, the behavior of the normal excitation current y1 due to this gradual excitation function may be to quickly increase the amount of power generation in the idle rotation or low load operation region or the normal operation region other than when the fuel is cut to quickly charge the power storage device 61. It is considered together. Therefore, there is a concern that an increase in mechanical load on the internal combustion engine 100 of the ISG 110 still destabilizes the engine rotation. Therefore, in the present embodiment, the control unit gradually increases the upper limit value of the excitation current by a predetermined value β every unit time α (for example, set to 8 milliseconds) repeatedly commanded by the ECU 0. The upper limit value is x2. Thereby, the behavior of the excitation current is effectively suppressed as the excitation current rises like the corrected excitation current y2. As a result, a temporary concentration of mechanical load on the internal combustion engine 100 is avoided, and a decrease in engine rotation in an idle operation or low load operation region is prevented.

  Further, in the present embodiment, as shown in FIG. 6, the predetermined value β, which is an increase amount of the command value for each command opportunity commanded by the ECU 0 per unit time α, is made variable according to the operation state at that time which is not normal. Yes. In other words, when an upper limit value that gradually increases is commanded to the generator, the predetermined value β, which is the increment of the upper limit value per unit time, is adjusted according to the operating state of the internal combustion engine 100.

  Next, the behavior of the terminal voltage, the excitation current, and the engine speed of the power storage device 61 when the control according to the present embodiment is executed will be described with reference to FIG.

  First, when the electric load increases, the terminal voltage of the power storage device 61 decreases as shown by the broken line in FIG. In order to quickly recover the decrease in the terminal voltage, control is performed to increase the amount of power generated by the ISG 110 and increase the output of the internal combustion engine 100. Here, the control for increasing the output of the internal combustion engine 100 includes control for increasing the opening degree of the throttle valve 32 in order to increase the target rotational speed. That is, the intake air amount is increased and the fuel injection amount is increased accordingly. At this time, in this embodiment, the behavior of the excitation current is one of the normal excitation current y1, the corrected excitation current y2 (idle), and y2 (F / C) depending on the operating state. That is, normal excitation current is taken during normal operation, corrected excitation current y2 (idle) during idle operation or low load operation region, and corrected excitation current y2 (F / C) during fuel cut. Here, if the behavior of the excitation current such as the normal excitation current y1 is taken when the operation state is in the idling operation, the low load operation region, or the fuel cut, the increase in the output of the internal combustion engine 100 increases the amount of power generation. Therefore, the engine speed drops and hunting occurs as shown by the broken line in FIG. In view of this, it is possible to effectively avoid the drop in the engine speed by appropriately taking one of the behaviors of the correction excitation current y2 (idle) and y2 (F / C) depending on the driving situation. .

  Here, the control for selecting one of the correction excitation currents y2 (idle) and y2 (F / C) is realized by making the value of the predetermined value β shown in FIG. 6 variable. That is, a different value according to each operation state such as idling operation or low load operation region or fuel cut, in other words, the value of the predetermined value β is set smaller in the former for the following reason. It is. During idle operation or in a low load operation region, the engine speed is low and the risk of engine stall is high, so the predetermined value β, which is “increment”, is decreased (excitation current is increased more slowly). On the other hand, since the engine speed is relatively high during the fuel cut, the excitation current is increased more quickly so that the power demand can be quickly met. In these situations, the predetermined value β may be increased as the engine speed or the vehicle speed increases. This is because the possibility of causing an engine stall is low.

  As another factor for setting the predetermined value β, the higher the temperature (cooling water temperature) of the internal combustion engine 100, the larger the friction loss and the easier the engine stalls. Furthermore, the higher the terminal voltage of the power storage device 61 (the charged state of the power storage device 61), the more power is stored, so the predetermined value β may be set smaller.

  By adopting the configuration as described above, in the present embodiment, the time until the value of the excitation current rises to a required value is appropriately delayed depending on the operating state. As a result, the increase in the output of the internal combustion engine 100 is not in time for the increase in the mechanical load caused by the ISG 110, thereby effectively avoiding the disadvantage that unnecessary engine speed reduction and hunting are caused. As a result, both stable driving of the internal combustion engine 100 and high charging efficiency of the ISG 110 are achieved.

  That is, conventionally, the excitation speed, that is, the increase speed of the excitation current is uniquely determined by the specifications of the controller 114 or the regulator that controls the power generation voltage of the ISG 110 (attached to the ISG 110), and the current operating range of the internal combustion engine 100 It was not considered to variably adjust according to the above. Therefore, in idling operation or in a low load operation region close to idling operation, the exciting current has a constant upper limit value x1 as shown in FIG. 6 even with the gradual excitation function by the controller 114 of the ISG 110. There is a concern that a mechanical load on the internal combustion engine 100 may destabilize the engine rotation by taking a behavior like the normal-time gradual excitation current y1. Therefore, as in the present embodiment, the above-mentioned concern is surely solved by paying attention for the first time and repeatedly performing the control of increasing by a predetermined value β per unit time α like the upper limit value x2. .

  Further, in the present embodiment, the excitation current of the excitation current is changed to a corrected excitation current y2 (idle), y2 (F / C) by changing the value of the predetermined value β according to the situation among the operation states that are not normal. The increase speed is set to the required speed according to the driving condition. As a result, the balance between avoiding a decrease in engine speed and charging / discharging is also more suitably maintained. In particular, when a lead battery, for example, is used as the power storage device 61, problems such as shortening of the life of the power storage device 61 and destabilization of the operation of the electrical system can be effectively solved.

  Although the embodiment of the present invention has been described above, the specific configuration of each unit is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the aspect in which the generator is an ISG that operates also as an electric motor is disclosed. However, the present invention can also be suitably applied to a vehicle to which an alternator that operates only as a generator is applied. Moreover, although the internal combustion engine provided with the electronic throttle valve was disclosed in the said embodiment, of course, you may apply this invention with respect to the internal combustion engine provided with the idle speed control valve. Further, specific modes of the power storage device and the electrical system are not limited to those of the above-described embodiment, and various modes including the existing ones can be applied.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  The present invention can be used as a control device for a vehicle equipped with an internal combustion engine and a generator that is driven by the internal combustion engine to generate electric power.

0 ... Vehicle control unit (ECU)
DESCRIPTION OF SYMBOLS 100 ... Internal combustion engine 110 ... Generator (ISG)

Claims (1)

A control device for a vehicle equipped with an internal combustion engine and a generator that is driven by the internal combustion engine to generate electric power,
It is possible to command the allowable upper limit of the exciting current flowing through the generator coil to the generator,
In a situation where the amount of power generated by the generator increases, whether to command a constant upper limit value for the excitation current to the generator or a command to the generator for a gradually increasing upper limit value of the internal combustion engine. Select according to the driving condition,
When commanding the gradually increasing upper limit value to the generator, the increment of the upper limit value per unit time is made smaller than the increase rate of the excitation current by the gradual excitation function during normal times during fuel cut, A control device that makes it smaller during low-load operation than during fuel cuts.

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