JP2008144591A - Control device for internal combustion engine and vehicle - Google Patents

Abstract

An internal combustion engine control device capable of further improving reliability during operation of the internal combustion engine, and a vehicle on which the internal combustion engine and the control device are mounted.
A control device for an engine 120 mounted on a hybrid vehicle 100 includes an HV_ECU 320 and an engine ECU 280. HV_ECU 320 sets a power command value for engine 120 based on the state of hybrid vehicle 100. When hunting of the power command value occurs, engine ECU 280 sets a fixed value in place of the power command value, and controls engine 120 so that the power output from engine 120 becomes the fixed value. .
[Selection] Figure 1

Description

  The present invention relates to a control device for controlling an internal combustion engine mounted on a vehicle, and a vehicle on which the internal combustion engine and the control device are mounted.

  Recently, hybrid vehicles have attracted attention as environmentally friendly vehicles. A hybrid vehicle is a vehicle that uses a DC power source, an inverter, and a motor driven by the inverter as a power source in addition to a conventional engine. In other words, a power source is obtained by driving the engine, a DC voltage from a DC power source is converted into an AC voltage by an inverter, and a motor is rotated by the converted AC voltage to obtain a power source.

For example, Japanese Patent Laid-Open No. 10-98803 (Patent Document 1) discloses a hybrid vehicle control device including vehicle drive power request value calculation means. The vehicle drive power request value calculation means calculates a vehicle drive torque command value for the hybrid vehicle based on at least operation information of an accelerator pedal, a brake pedal, and a shift lever. The vehicle drive power request value calculation means further calculates a vehicle drive power request value based on the calculated vehicle drive torque command value and the vehicle speed of the hybrid vehicle.
JP-A-10-98803

  In the above hybrid vehicle, the power to be output to the internal combustion engine is determined according to the vehicle drive power request value. If the required value fluctuates in a short cycle and the fluctuation range of the required value is small, the internal combustion engine may not be able to operate following the fluctuation of the required value. Nevertheless, when the internal combustion engine is controlled to operate the internal combustion engine in accordance with the required value, it is considered that some influence is exerted on the operation of the internal combustion engine. However, Japanese Patent Laid-Open No. 10-98803 (Patent Document 1) does not particularly disclose the possibility of such a problem.

  An object of the present invention is to provide a control device for an internal combustion engine capable of further improving the reliability during operation of the internal combustion engine, and a vehicle equipped with the internal combustion engine and the control device.

  In summary, the present invention is a control device for an internal combustion engine mounted on a vehicle, wherein a setting unit that sets a power command value for the internal combustion engine based on the state of the vehicle, and an internal combustion engine according to the power command value And a control unit for controlling. When hunting of the power command value occurs, the control unit sets a fixed value instead of the power command value, and controls the internal combustion engine so that the power output from the internal combustion engine becomes a fixed value.

  Preferably, the control device further includes a monitoring unit that monitors the state of the internal combustion engine. The control unit determines whether hunting of the power command value has occurred based on the monitoring result from the monitoring unit and the power command value.

  More preferably, the internal combustion engine has a throttle valve that adjusts its intake air amount. The control device further includes a motor that drives the throttle valve to change the opening of the throttle valve. The monitoring unit monitors the motor current flowing through the motor.

  More preferably, when the motor current changes according to the power command value and the peak value of the motor current exceeds a value corresponding to the power command value, the control unit continues for a predetermined period. It is determined that hunting of the power command value has occurred.

  Preferably, when the hunting of the power command value occurs, the control unit acquires the upper limit value and the lower limit value in the fluctuation range of the power command value, and sets one of the upper limit value and the lower limit value as a fixed value. .

  More preferably, the control unit sets one of the upper limit value and the lower limit value to a fixed value, and sets the other of the upper limit value and the lower limit value to a fixed value after a predetermined period has elapsed.

  More preferably, when the power command value is larger than the upper limit value, the control unit ends the control of the internal combustion engine based on the fixed value, and controls the internal combustion engine based on the power command value.

  When the other situation of this invention is followed, it is a vehicle, Comprising: An internal combustion engine and the control apparatus in any one of the above-mentioned are provided.

  ADVANTAGE OF THE INVENTION According to this invention, the reliability at the time of operation | movement of the vehicle carrying an internal combustion engine can be improved more.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

  FIG. 1 is a block diagram of a hybrid vehicle equipped with a control device for an internal combustion engine according to an embodiment of the present invention.

  Referring to FIG. 1, hybrid vehicle 100 includes an internal combustion engine (hereinafter simply referred to as an engine) 120 such as a gasoline engine and a motor generator (MG) 140 as drive sources. In the following, for convenience of explanation, motor generator 140 is expressed as motor 140A and generator 140B (or motor generator 140B). However, depending on the traveling state of the hybrid vehicle 100, the motor 140A functions as a generator, or the generator 140B functions as a motor. Regenerative braking is performed when this motor generator functions as a generator. When the motor generator functions as a generator, the kinetic energy of the vehicle is converted into electric energy and the vehicle is decelerated.

  Hybrid vehicle 100 further includes a reduction gear 180 and a power split mechanism (for example, a planetary gear mechanism) 200. Reducer 180 transmits the power generated by engine 120 and motor generator 140 to drive wheel 160, and transmits the drive of drive wheel 160 to engine 120 and motor generator 140. Power split device 200 distributes the power generated by engine 120 to two paths of drive wheel 160 and generator 140B. Thus, reduction gear 180 and power split mechanism 200 transmit driving force from at least one of the internal combustion engine and the electric motor to the wheels.

  Hybrid vehicle 100 further includes a traveling battery 220 and an inverter 240. Traveling battery 220 is charged with electric power for driving motor generator 140. Inverter 240 performs current control while converting the DC voltage of battery for traveling 220 and the AC voltage of motor 140A and generator 140B.

  Hybrid vehicle 100 further includes a battery control unit (hereinafter referred to as a battery ECU (Electronic Control Unit)) 260, engine ECU 280, MG_ECU 300, and HV_ECU 320.

  Battery ECU 260 manages and controls the charge / discharge state of battery for traveling 220. Engine ECU 280 controls the operating state of engine 120. MG_ECU 300 controls motor generator 140, battery ECU 260, and inverter 240 in accordance with the state of hybrid vehicle 100. HV_ECU 320 mutually manages and controls battery ECU 260, engine ECU 280, and MG_ECU 300. The HV_ECU 320 controls the entire hybrid system so that the hybrid vehicle 100 can operate most efficiently.

  In the present embodiment, boost converter 242 is provided between battery for traveling 220 and inverter 240. This is because the rated voltage of battery for traveling 220 is lower than the rated voltage of motor 140A or motor generator 140B. When power is supplied from running battery 220 to motor 140A or motor generator 140B, voltage is boosted by boost converter 242.

  In FIG. 1, each ECU is configured separately, but two or more ECUs may be integrated and configured as one ECU. For example, MG_ECU 300 and HV_ECU 320 may be integrated into a single ECU as indicated by a broken line frame in FIG. As another example, engine ECU 280, MG_ECU 300, and HV_ECU 320 may be integrated into a single ECU, for example.

  The power split mechanism 200 uses a planetary gear mechanism (planetary gear) in order to distribute the power of the engine 120 to both the drive wheel 160 and the motor generator 140B. By controlling the rotation speed of motor generator 140B, power split device 200 also functions as a continuously variable transmission. The rotational force of engine 120 is input to planetary carrier (C), which is transmitted to motor generator 140B by sun gear (S) and to the motor and output shaft (drive wheel 160 side) by ring gear (R). When the rotating engine 120 is stopped, since the engine 120 is rotating, the kinetic energy of this rotation is converted into electric energy by the motor generator 140B, and the rotational speed of the engine 120 is reduced.

  In the hybrid vehicle 100, when the engine 120 is started, an operation (cranking) of rotating the crankshaft of the engine 120 is performed by the generator 140B.

  When the engine 120 is inefficient, such as when starting or running at a low speed, the hybrid vehicle 100 is driven only by the motor 140A of the motor generator 140. During normal traveling, for example, the power of the engine 120 is divided into two paths by the power split mechanism 200. The driving wheel 160 is directly driven by one of the two divided powers, and the generator 140B is driven by the other to generate power. The motor 140A is driven by the electric power generated at this time to assist driving of the driving wheels 160.

  Further, during high-speed traveling, electric power from the traveling battery 220 is further supplied to the motor 140A to increase the output of the motor 140A and add driving force to the driving wheels 160.

  On the other hand, at the time of deceleration, motor 140 </ b> A driven by drive wheel 160 functions as a generator to perform regenerative power generation, and the collected power is stored in traveling battery 220. When the charging amount of traveling battery 220 is reduced and charging is particularly necessary, the output of engine 120 is increased to increase the amount of power generated by generator 140B to increase the charging amount for traveling battery 220.

  FIG. 2 is a schematic configuration diagram showing an internal combustion engine (engine 120) controlled by the control device for the internal combustion engine according to the present embodiment.

  Referring to FIG. 2, engine 120 is an internal combustion engine in which an air-fuel mixture of air sucked from air cleaner 102 and fuel injected from injector 104 is ignited and burned by a spark plug 106 in a combustion chamber.

  When the air-fuel mixture burns, the piston 108 is pushed down by the combustion pressure, and the crankshaft 110 rotates. The combusted air-fuel mixture (exhaust gas) is purified by the three-way catalyst 112 and then discharged outside the vehicle. The amount of air taken into engine 120 is adjusted by throttle valve 114.

  When the crankshaft 110 rotates, intake and exhaust camshafts (not shown) connected by a chain or a belt are rotated. The intake valve 116 and the exhaust valve 118 provided at the upper part of the cylinder of the engine 120 are opened and closed by the rotation of the intake and exhaust camshafts. By opening the exhaust valve 118, the exhaust gas after combustion in the cylinder is exhausted to the outside. When the intake valve 116 is opened, the air-fuel mixture flows into the cylinder.

  The cam timing on the intake side of the engine 120 is further provided with a variable valve timing mechanism 122. Note that a variable valve timing mechanism may also be provided on the camshaft on the exhaust side. The variable valve timing mechanism 122 is a mechanism that varies the opening / closing timing of the intake valve 116.

  Engine ECU 280 includes knock sensor 294, water temperature sensor 302, crank position sensor 292 provided opposite to timing rotor 290, throttle opening sensor 288, vehicle speed sensor 284, ignition switch 286, and throttle motor. 296 and a current sensor 297 are connected. A vehicle speed sensor 284 is connected to the HV_ECU 320.

  Knock sensor 294 is composed of a piezoelectric element. Knock sensor 294 generates a voltage due to vibration of engine 120. The magnitude of the voltage corresponds to the magnitude of the vibration. Knock sensor 294 transmits a signal representing the voltage to engine ECU 280.

  Water temperature sensor 302 detects the temperature of cooling water in the water jacket of engine 120 and transmits a signal representing the detection result to engine ECU 280.

  The timing rotor 290 is provided on the crankshaft 110 and rotates together with the crankshaft 110. A plurality of protrusions are provided on the outer periphery of the timing rotor 290 at predetermined intervals. The crank position sensor 292 is provided to face the protrusion of the timing rotor 290. When the timing rotor 290 rotates, the air gap between the protrusion of the timing rotor 290 and the crank position sensor 292 changes, so that the magnetic flux passing through the coil portion of the crank position sensor 292 increases and decreases, and an electromotive force is generated in the coil portion. .

  Crank position sensor 292 transmits a signal representing the electromotive force to engine ECU 280. Engine ECU 280 detects the crank angle based on the signal transmitted from crank position sensor 292.

  Throttle opening sensor 288 detects the throttle opening and transmits a signal representing the detection result to engine ECU 280. Vehicle speed sensor 284 detects the number of rotations of a wheel (not shown) and transmits a signal representing the detection result to engine ECU 280. Engine ECU 280 calculates the vehicle speed from the rotational speed of the wheel. The ignition switch 286 is turned on by the driver when the engine 120 is started.

  Engine ECU 280 performs arithmetic processing based on the signals transmitted from each sensor and ignition switch 286, a map and a program stored in a memory (not shown) in engine ECU 280, and engine 120 enters a desired operating state. So that the equipment is controlled.

  Control device 310 is a control device for an internal combustion engine according to the present embodiment. Control device 310 includes engine ECU 280, HV_ECU 320, throttle motor 296, and current sensor 297. The HV_ECU 320 calculates the power (power) required for the hybrid vehicle 100 based on the situation of the hybrid vehicle 100 (vehicle speed, accelerator opening, etc.). Furthermore, HV_ECU 320 determines the distribution of the power output from engine 120 and the power output from motor 140A in FIG. 1 based on the power required for the vehicle.

  The engine ECU 280 receives the engine output power command value from the HV_ECU 320 and controls the engine 120 so that the power output from the engine 120 becomes the command value. Specifically, engine ECU 280 calculates the opening of throttle valve 114 (throttle opening TH) based on a command value of engine output power. Engine ECU 280 then sends a signal indicating throttle opening TH to throttle motor 296 to operate throttle motor 296.

  Throttle motor 296 drives throttle valve 114 in response to a signal from engine ECU 280. As a result, the opening degree of the throttle valve 114 changes. The throttle motor 296 is a DC motor, for example.

  Current sensor 297 detects a motor current flowing through throttle motor 296 and outputs a motor current value (current value Im) to engine ECU 280.

  Based on the engine output power command value from HV_ECU 320, engine ECU 280 controls engine 120 so that the output power of engine 120 becomes the engine output power command value. However, when engine output power command value hunting occurs, engine ECU 280 sets a fixed value in place of the engine output power command value. Engine ECU 280 controls engine 120 such that the power output from engine 120 has a fixed value. Thereby, it is possible to further improve the reliability of the engine 120 during operation.

  FIG. 3 is a block diagram showing a configuration of a main part of HV_ECU 320 in FIGS. 1 and 2.

  Referring to FIG. 3, HV_ECU 320 includes a required torque determining unit 321, a multiplying unit 322, an adding unit 323, and a driving force distribution determining unit 324.

  Requested torque determination unit 321 receives information on accelerator opening A from accelerator opening sensor 298. The accelerator opening sensor 298 is provided corresponding to an accelerator pedal (not shown). When the driver depresses the accelerator pedal, the accelerator opening sensor 298 outputs a voltage corresponding to the depression amount of the accelerator pedal. This output voltage is sent to the required torque determining unit 321 as information on the accelerator opening A.

  Requested torque determination unit 321 receives information on vehicle speed V of hybrid vehicle 100 in FIG. The required torque determining unit 321 stores in advance a map M1 in which the accelerator opening A, the vehicle speed V, and the required torque T are associated with each other, and determines the required torque T by referring to this map M1.

  The multiplying unit 322 calculates the traveling power P by the product of the required torque T and the vehicle speed V (P = T × V). Adder 323 receives travel power P from multiplier 322 and receives a value SOC indicating the state of charge of travel battery 220 from battery ECU 260 in FIG. Adder 323 adds running power P and state of charge SOC to calculate the power required for the vehicle (vehicle required power PW).

  The driving force distribution determining unit 324 receives the vehicle required power PW and determines the driving force distribution between the engine 120 (FIG. 1) and the motor 140A (FIG. 1). The driving force distribution determination unit 324 determines the driving force distribution in accordance with the driving situation of the vehicle in consideration of the efficiency of the engine 120 in terms of fuel consumption. That is, driving force distribution determination unit 324 determines engine output power command value Pe for engine 120 and motor output power command value Pm for motor 140A.

  The engine output power command value Pe output from the engine 120 is determined in consideration of increasing the engine efficiency (that is, fuel consumption). Specifically, as shown in FIG. 4, the operating point of the engine is determined along an engine operating range set in advance on a plane indicated by the engine speed and the engine torque. Further, an engine output power command value Pe is determined corresponding to the determined engine operating point. Driving force distribution determining unit 324 outputs engine output power command value Pe and engine speed Ne to engine ECU 280.

  Then, the driving force distribution determination unit 324 sets the shortage with respect to the vehicle required power PW as the motor output power command value Pm by the motor 140A (FIG. 1). That is, basically, driving force distribution as shown in the following equation (1) is performed.

Pm = PW−Pe (1)
Motor output power command value Pm is output to MG_ECU 300 shown in FIG. The MG_ECU 300 generates a switching control signal for the semiconductor switching elements constituting the inverter 240 so that torque corresponding to the motor output power command value Pm is output. The inverter 240 supplies an AC output necessary for generating the torque to the motor 140A by power conversion according to the switching control signal.

  Further, the driving force distribution determination unit 324 performs motoring when the engine 120 is motored by the generator 140B (when the output of the engine 120 becomes 0 by rotating the engine 120 by the generator 140B). A signal MTR indicating that the engine is running is output to engine ECU 280. For example, when the value of signal MTR indicates “1” (for example, when the level of signal MTR is H level), it indicates that engine 120 is motoring, and the value of signal MTR indicates “0”. The case (when the level of the signal MTR is the H level) indicates that the engine 120 is not motored (for example, the engine 120 is stopped or is operating independently).

FIG. 5 is a block diagram showing a configuration of a main part of engine ECU 280.
Referring to FIG. 5, engine ECU 280 includes a division unit 281, a throttle opening calculation unit 282, and a command value fixing processing unit 283.

  Command value fixing processing unit 283 receives engine output power command value Pe and signal MTR from HV_ECU 320. Further, the command value fixing processing unit 283 receives the current value Im from the current sensor 297 (FIG. 2). When it is determined that hunting of the engine output power command value Pe has occurred, the command value fixing processing unit 283 sets the output set value Peo to a fixed value, otherwise, the output set value Peo is output to the engine. Set to the same value as the power command value Pe. Further, the command value fixing processing unit 283 sets the output set value Peo to the same value as the engine output power command value Pe when the value of the signal MTR is “1”.

  The command value fixing processing unit 283 determines whether hunting of the engine output power command value Pe occurs based on the engine output power command value Pe and the current value Im. Thereby, it is possible to accurately determine whether or not hunting of the engine output power command value Pe occurs.

  If the command value fixing processing unit 283 determines whether or not the hunting of the engine output power command value Pe has occurred based only on the fluctuation of the engine output power command value Pe, an erroneous determination may occur. . For example, when the driver operates the accelerator pedal finely, the engine output power command value Pe may also vary finely. In this case, if the engine output power command value Pe is fixed, the responsiveness of the operation of the vehicle may be lowered. According to the present embodiment, it is possible to prevent such a problem from occurring.

  Division unit 281 receives output set value Peo from command value fixing processing unit 283 and receives engine speed Ne from HV_ECU 320. The division unit 281 divides the output set value Peo by the engine speed Ne to obtain the engine torque Te (Te = Peo / Ne).

  The throttle opening calculation unit 282 receives the engine torque Te and the engine speed Ne. The throttle opening calculation unit 282 stores in advance a map M3 in which the throttle opening TH, the engine torque Te, and the engine speed Ne are associated with each other. The throttle opening degree calculation unit 282 calculates the throttle opening degree TH based on the map M3.

  FIG. 6 is a functional block diagram showing a configuration of the command value fixing processing unit 283 shown in FIG. Note that the command value fixing processing unit 283 illustrated in FIG. 6 may be realized by hardware or may be realized by software.

  Referring to FIG. 6, command value fixing processing unit 283 includes overcurrent detection frequency counter 351, release processing counter 352, upper limit value specification frequency counter 353A, lower limit value specification frequency counter 353B, and command value setting unit. 354.

  The command value setting unit 354 calculates the value of the motor current flowing through the throttle motor 296 (FIG. 2) corresponding to the engine output power command value Pe at every predetermined time, and calculates the calculated motor current value and the current value Im. And compare. Then, the command value setting unit 354 determines that an overcurrent has flowed through the throttle motor 296 when the current value Im is larger than the calculated motor current value by a predetermined value or more. Each time the command value setting unit 354 determines that an overcurrent has flowed through the throttle motor 296, the command value setting unit 354 sends an instruction to the overcurrent detection number counter 351 to increase the count value CNT by one.

  The command value setting unit 354 receives the count value CNT from the overcurrent detection number counter 351. When the count value CNT exceeds the threshold value Cth1, the command value setting unit 354 thereafter sets the output set value Peo to a fixed value regardless of the input engine output power command value Pe.

  On the other hand, when the command value setting unit 354 determines that the current value Im is not an overcurrent, the command value setting unit 354 sends an instruction to the release processing counter 352. The cancellation processing counter 352 increases the count value RCNT by 1 each time an instruction is received from the command value setting unit 354.

  The command value setting unit 354 receives the count value RCNT from the release processing counter 352. Command value setting unit 354 sets output setting value Peo to the same value as engine output power command value Pe when count value RCNT exceeds threshold value Cth2. That is, the engine output power command value Pe is released.

  When command value setting unit 354 determines that hunting of engine output power command value Pe is occurring, it acquires an upper limit value and a lower limit value in the fluctuation range of engine output power command value Pe. The command value setting unit 354 sends an instruction to the upper limit value designated number counter 353A every time the engine output power command value Pe reaches the upper limit value in the fluctuation range. The upper limit value designated number counter 353A increases the count value by one each time an instruction is received.

  Further, the command value setting unit 354 sends an instruction to the lower limit value designated number counter 353B every time the engine output power command value Pe reaches the lower limit value in the fluctuation range. The lower limit value designated number counter 353B increases the count value by one each time an instruction is received.

  The command value setting unit 354 sets the output set value Peo based on the count value of the upper limit value specified number counter 353A and the count value of the lower limit value specified number counter 353B. Hereinafter, the processing of the command value fixing processing unit 283 will be described in detail.

<Control processing by command value fixing processing section>
FIG. 7 is a diagram for explaining problems that may occur during hunting of the engine output power command value Pe.

  Referring to FIG. 7, for example, in the feedback control process for charging / discharging the traveling battery in order to establish the power balance of hybrid vehicle 100 (FIG. 1), periodic hunting of engine output power command value Pe occurs. . At this time, the engine output power command value Pe periodically varies between the upper limit value Pe1 and the lower limit value Pe2. The difference between the upper limit Pe1 and the lower limit Pe2 is, for example, 1 kW.

  For easy understanding, it is assumed that the upper limit Pe1 is 1 kW and the lower limit Pe2 is 0 kW, for example. Further, it is assumed that the cycle of fluctuation of the engine output power command value Pe is a short cycle (for example, a cycle of about 8 milliseconds). In the present embodiment, “the state in which hunting of the engine output power command value Pe is occurring” means a state in which the fluctuation cycle of the engine output power command value Pe is short and the fluctuation range is small as shown in FIG. Point to.

  As a situation where the engine output power command value Pe fluctuates in this way, for example, a case where the traveling battery 220 in FIG. 1 is charged with power and the charging power is small can be considered. In this case, the HV_ECU 320 attempts to bring the charging state of the traveling battery 220 closer to the target state by finely changing the magnitude of the engine output power command value Pe and reducing the width of the change.

  When the command value fixing processing unit 283 shown in FIG. 5 always makes the output set value Peo equal to the engine output power command value Pe (the engine output power command value Pe is not fixed), the engine output power command value Pe. Changes from the lower limit Pe2 to the upper limit Pe1, the value of the throttle opening TH output from the throttle opening calculator 282 in FIG. 5 changes from TH1 to TH2. Conversely, when the engine output power command value Pe changes from the upper limit value Pe1 to the lower limit value Pe2, the value of the throttle opening TH changes from TH2 to TH1.

  When the value of the throttle opening TH changes in this way, the operation of the throttle motor 296 repeats normal rotation and reverse rotation. For this reason, the direction and magnitude of the current flowing through the throttle motor 296 also change frequently. The current value Im frequently changes around a reference value Im0 (for example, Im = 0).

  For example, when the throttle opening TH changes from TH2 to TH1 or from TH1 to TH2, the current value Im also changes suddenly from Im0, and the current value Im has a sharp peak (peaks PK1, PK2). Arise. However, due to the inertia of the throttle motor 296, the rotation direction of the throttle motor 296 cannot be immediately switched between the forward rotation direction and the reverse rotation direction. In short, when hunting of the engine output power command value Pe occurs, the throttle motor 296 cannot operate following the fluctuation of the engine output power command value Pe.

  As a result, an inrush current as indicated by peaks PK1 and PK2 flows through the coil of the throttle motor 296. As a result, heat is generated in the coil, so that the temperature of the throttle motor 296 rises. If hunting of the engine output power command value Pe continues for a long time, the temperature of the throttle motor 296 rises excessively, and the probability that the throttle motor 296 will fail increases.

  Such a phenomenon may or may not occur depending on the operation of the accelerator pedal by the user or the traveling state of the vehicle. Therefore, it is difficult to configure the control system so that hunting of the engine output power command value Pe does not occur at all.

  In this embodiment, when hunting of the engine output power command value Pe occurs, the command value is fixed. As a result, the value of the current flowing through the throttle motor can be stabilized.

  FIG. 8 is a flowchart for explaining control processing by the command value fixing processing unit 283 in FIG.

  Referring to FIGS. 8 and 6, first, command value setting unit 354 determines whether or not the motor current flowing through the throttle motor is an overcurrent based on current value Im (step S1). The command value setting unit 354 calculates the value of the motor current flowing through the throttle motor 296 (FIG. 2) corresponding to the engine output power command value Pe, and compares the calculated motor current value with the current value Im. The command value setting unit 354 determines that the motor current is an overcurrent when the current value Im is greater than a predetermined value with respect to the calculated motor current value, and the current value Im with respect to the calculated motor current value. If Im is less than the predetermined value, it is determined that the motor current is not an overcurrent.

  When the motor current is an overcurrent (YES in step S1), the command value setting unit 354 sends an instruction to increase the count value CNT to the overcurrent detection number counter 351. The overcurrent detection number counter 351 increases the count value CNT by 1 according to the instruction (step S2). On the other hand, when the motor current is not an overcurrent (NO in step S1), command value setting unit 354 sends an instruction to increase count value RCNT to release processing counter 352. The cancellation processing counter 352 increases the count value RCNT by 1 according to the instruction (step S3).

  After the process of step S2 or step S3, the command value setting unit 354 acquires the count value CNT from the overcurrent detection number counter 351. The command value setting unit 354 determines whether or not the count value CNT is greater than the threshold value Cth1 (step S4).

  When count value CNT is larger than threshold value Cth1 (YES in step S4), command value setting unit 354 turns on the fixed processing function (step S5). The command value setting unit 354 stores a flag therein, and sets the flag to “1” when the fixed processing function is turned on. Further, the command value setting unit 354 sends an instruction to the release processing counter 352 to set the count value RCNT to 0, and sends an instruction to the overcurrent detection number counter 351 to set the count value CNT to 0 (step S6). .

  Note that once the fixed processing function is turned on in step S5, the engine output power command value Pe is fixed until the fixed processing function is turned off. Therefore, even if the count value CNT is set to 0 in step S6, the subsequent command value fixing process is not affected.

  On the other hand, when count value CNT is smaller than threshold value Cth1 (NO in step S4), command value setting unit 354 acquires count value RCNT from release processing counter 352. Command value setting unit 354 determines whether or not count value RCNT is greater than threshold value Cth2 (step S7).

  When count value RCNT is larger than threshold value Cth2 (YES in step S7), command value setting unit 354 turns off the fixed processing function (step S8). In step S8, the command value setting unit 354 sets the flag stored therein to “0”.

  After the process of step S6 or step S8, the command value setting unit 354 refers to the flag to determine whether the fixed process function is on or off (step S9). When the fixed processing function is turned on, the command value setting unit 354 first performs command value fixing processing (step S10), and then performs exception processing (step S11). Details of the command value fixing process and the exception process will be described later.

  On the other hand, when the fixed processing function is turned off, the command value setting unit 354 performs a release process (step S12). The canceling process is a process of canceling the fixation of the engine output power command value Pe, and specifically, a process of setting the output set value Peo to be the same as the engine output power command value Pe.

When the process of step S11 or step S12 ends, the entire process ends.
FIG. 9 is a flowchart illustrating the command value fixing process in step S10 of FIG.

  Referring to FIGS. 9 and 6, first, command value setting unit 354 obtains upper limit value Pe1 and lower limit value Pe2 of engine output power command value Pe (see FIG. 7) (step S21). Next, the command value setting unit 354 determines whether or not the engine output power command value Pe is equal to or lower than the upper limit value Pe1 (step S22).

  The engine output power command value Pe being equal to or lower than the upper limit value Pe1 means that the engine output power command value Pe varies between the upper limit value Pe1 and the lower limit value Pe2, that is, the engine output power command value Pe Hunting has occurred. In this case (YES in step S22), command value setting unit 354 sets output setting value Peo to lower limit value Pe2 (step S23). On the other hand, if the engine output power command value Pe is larger than the upper limit value Pe1 in step S22 (NO in step S22), the entire process ends.

  After the process of step S23, the command value setting unit 354 counts to increase the count value of the upper limit value designated number counter 353A and the count value of the lower limit value designated number counter 353B based on the input engine output power command value Pe. Processing is performed (step S24). When the engine output power command value Pe is the upper limit value Pe1, the command value setting unit 354 sends an instruction to the upper limit value designated number counter 353A to increase the count value of the upper limit value designated number counter 353A. On the other hand, when engine output power command value Pe is lower limit value Pe2, command value setting unit 354 sends an instruction to lower limit value designated number counter 353B to increase the count value of lower limit value designated number counter 353B. This counting process is executed for a predetermined period.

  Subsequently, the command value setting unit 354 determines whether or not the number of times that the engine output power command value Pe has reached the upper limit value Pe1 is X times (X is a predetermined value) based on the count value of the upper limit value designation number counter 353A. Determine whether. When the engine output power command value Pe is the upper limit value Pe1 X times continuously (YES in step S25), the command value setting unit 354 sets the output setting value Peo to the upper limit value Pe1 (step S26). When the process of step S26 ends, the entire process ends. On the other hand, if the number of times that engine output power command value Pe reaches upper limit value Pe1 has not reached X times (NO in step S25), command value setting unit 354 executes the determination process in step S27.

  In step S27, the command value setting unit 354 determines that the number of times that the engine output power command value Pe has reached the lower limit value Pe2 is Y times (Y is a predetermined value different from X) based on the count value of the lower limit value designation number counter 353B. It is determined whether or not it is continuous. If the engine output power command value Pe is the lower limit Pe2 continuously for Y times (YES in Step S27), the command value setting unit 354 sets the output set value Peo to the lower limit Pe2 (Step S28). When the process of step S28 ends, the entire process ends.

  On the other hand, if the number of times that engine output power command value Pe reaches lower limit value Pe2 has not reached Y times (NO in step S27), command value setting unit 354 ends the entire process.

  As described above, when the engine output power command value Pe fluctuates in a short cycle and the fluctuation range is small, for example, the battery 220 for traveling in FIG. Is small. In this case, the HV_ECU 320 changes the engine output power command value Pe in a short cycle and makes the change width small so as to bring the charging state of the traveling battery 220 closer to the target state. By performing the processing of step S23 and step S26, the output set value Peo is first fixed to the lower limit value Pe2, and then fixed to the upper limit value Pe1.

  Thereby, for example, even when the charging power of the traveling battery 220 is small, the charging state of the traveling battery 220 can be brought close to the target state while stabilizing the current flowing through the throttle motor. The above-mentioned X times and Y times respectively define a period in which Peo = Pe1 and a period in which Peo = Pe2. The values of X and Y may be fixed values, for example, or may be determined according to the charging power of the traveling battery 220 or the like.

FIG. 10 is a flowchart for explaining the exception processing in step S11 of FIG.
Referring to FIG. 10, in step S31, command value setting unit 354 determines whether or not engine output power command value Pe is equal to or greater than predetermined value Pe3 (step S31). The predetermined value Pe3 is larger than the upper limit value Pe1 of the engine output power command value Pe shown in FIG.

  When engine output power command value Pe is greater than or equal to predetermined value Pe3 (YES in step S31), command value setting unit 354 sets output set value Peo equal to input engine output power command value Pe (step S32). If the engine output power command value Pe is equal to or greater than the predetermined value Pe3, it is considered that hunting of the engine output power command value Pe has not occurred. Therefore, in step S32, the command value setting unit 354 releases the fixed engine output power command value Pe.

  On the other hand, when engine output power command value Pe is less than predetermined value Pe3 (NO in step S31), command value setting unit 354 determines whether the value of signal MTR is “1” or “0” ( Step S33).

  When the value of signal MTR is 1 (YES in step S33), command value setting unit 354 makes output set value Peo equal to input engine output power command value Pe (step S32). When the process of step S32 is completed and when the value of the signal MTR is “0” (NO in step S33), the entire process is completed.

FIG. 11 is a diagram for explaining the effect of the present embodiment.
Referring to FIG. 11, according to the present embodiment, when engine output power command value Pe hunting occurs, output set value Peo is fixed to one of upper limit value Pe1 and lower limit value Pe2. As a result, the value of the throttle opening TH output from the throttle opening calculation unit 282 in FIG. 5 is also fixed to either the value TH1 or the value TH2. As a result, the current value Im becomes either the current value Im1 or the current value Im2, and the current flowing through the throttle motor is stabilized.

  The present embodiment will be comprehensively described again. Referring to FIGS. 1 and 2, control device 310 for engine 120 mounted on hybrid vehicle 100 includes HV_ECU 320 and engine ECU 280. As shown in FIG. 3, HV_ECU 320 sets an engine output power command value Pe that is a power command value for engine 120 based on the state of hybrid vehicle 100. As shown in FIG. 5, engine ECU 280 controls engine 120 in accordance with engine output power command value Pe. When engine hunting of engine output power command value Pe occurs, engine ECU 280 sets a fixed value in place of engine output power command value Pe so that the power output from engine 120 becomes the fixed value. The engine 120 is controlled. As a result, even when hunting of the engine output power command value Pe occurs, the engine 120 can be stably operated, so that the reliability during operation of the internal combustion engine can be further improved.

  As shown in FIG. 2, control device 310 preferably further includes a monitoring unit (current sensor 297) that monitors the state of engine 120. Engine ECU 280 determines whether hunting of engine output power command value Pe has occurred or not based on the monitoring result (current value Im) from the monitoring unit and engine output power command value Pe.

  More preferably, engine 120 has a throttle valve 114 that adjusts its intake air amount. The control device 310 further includes a throttle motor 296 that drives the throttle valve 114 to change the opening degree of the throttle valve 114. A current sensor 297 serving as a monitoring unit monitors the motor current flowing through the throttle motor 296.

  More preferably, engine ECU 280 changes the motor current according to engine output power command value Pe, and the peak values of motor current (peaks PK1, PK2 shown in FIG. 7) correspond to engine output power command value Pe. When the state exceeding the value continues for a predetermined period (when the count value CNT shown in FIG. 6 is larger than the threshold value Cth1), it is determined that hunting of the engine output power command value Pe occurs.

  Thereby, it is possible to accurately determine whether or not hunting of the engine output power command value Pe occurs.

  Further, it is possible to prevent an inrush current having a sharp peak waveform such as peaks PK1 and PK2 shown in FIG. 7 from flowing into the coil of the throttle motor. Thereby, excessive heat generation in the coil of the throttle motor can be suppressed.

  Preferably, engine ECU 280 acquires upper limit value Pe1 and lower limit value Pe2 in the fluctuation range of engine output power command value Pe when hunting of engine output power command value Pe occurs. Engine ECU 280 sets one of upper limit value Pe1 and lower limit value Pe2 as a fixed value.

  More preferably, referring to FIG. 9, engine ECU 280 sets one of upper limit value Pe1 and lower limit value Pe2 to a fixed value, and after a predetermined period has elapsed (engine output power command value Pe is equal to upper limit value Pe1). After the number of times reaches X), the other of the upper limit Pe1 and the lower limit Pe2 is set to a fixed value. Thereby, power can be stably output from engine 120, and the integrated value of power output from engine 120 can be set to a desired magnitude.

  In the flowchart shown in FIG. 9, the output set value Peo is set to the upper limit value Pe1 after the output set value Peo is set to the lower limit value Pe2 (steps S23 and S26), but the output set value Peo is set to the upper limit value. The output set value Peo may be set to the lower limit value Pe2 after being set to the value Pe1.

  More preferably, when engine output power command value Pe is larger than upper limit value Pe1 (when Pe ≧ P3), engine ECU 280 ends control of engine 120 based on the fixed value, and engine output power command value Pe. Based on the above, engine 120 is controlled. Thereby, the state in which the engine output power command value Pe is fixed can be quickly released.

  Furthermore, according to the present embodiment, by mounting control device 310 described above in hybrid vehicle 100, the reliability during operation of hybrid vehicle 100 can be further improved.

  The vehicle including the control device for an internal combustion engine of the present invention is not limited to the hybrid vehicle as shown in the present embodiment. For example, the present invention is applicable to a vehicle that requires information other than the user's operation of an accelerator pedal when determining the driving force. More specifically, the present invention can be used, for example, in a vehicle equipped with a function (so-called auto-cruise function) for traveling while maintaining a certain distance from the preceding vehicle during traveling. In such a vehicle, it is necessary to set the driving force and the engine output in accordance with various conditions such as the inter-vehicle distance and the slope of the road surface. Therefore, the present invention can also be applied to such a vehicle.

  In this embodiment, when engine output power command value Pe is fluctuating, output set value Peo is fixed to either upper limit value Pe1 or lower limit value Pe2 of engine output power command value Pe. However, the output set value Peo is not limited to be fixed to one of the upper limit value Pe1 and the lower limit value Pe2, for example, a value between the upper limit value Pe1 and the lower limit value Pe2 (for example, the upper limit value Pe1 and the lower limit value Pe2). (Average value) may be set.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a block diagram of a hybrid vehicle equipped with a control device for an internal combustion engine according to an embodiment of the present invention. It is a schematic block diagram which shows the internal combustion engine (engine 120) controlled by the control apparatus of the internal combustion engine according to the present embodiment. FIG. 3 is a block diagram showing a configuration of a main part of HV_ECU 320 in FIGS. 1 and 2. It is a conceptual diagram explaining the setting of an engine operating point. It is a block diagram showing a configuration of a main part of engine ECU 280. It is a functional block diagram which shows the structure of the command value fixing process part 283 shown in FIG. It is a figure explaining the problem which may arise at the time of hunting of engine output power command value Pe. It is a flowchart explaining the control processing by the command value fixed process part of FIG. It is a flowchart explaining the command value fixing process of step S10 of FIG. It is a flowchart explaining the exception process of step S11 of FIG. It is a figure explaining the effect by this Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 Hybrid vehicle, 102 Air cleaner, 104 Injector, 106 Spark plug, 108 Piston, 110 Crankshaft, 112 Three-way catalyst, 114 Throttle valve, 116 Intake valve, 118 Exhaust valve, 120 Engine, 122 Valve timing variable mechanism, 140 Motor generator , 160 drive wheels, 180 speed reducer, 200 power split mechanism, 220 battery for traveling, 240 inverter, 242 boost converter, 260 battery ECU, 280 engine ECU, 281 division unit, 282 throttle opening calculation unit, 283 command value fixing process , 284 vehicle speed sensor, 286 ignition switch, 288 throttle opening sensor, 290 timing rotor, 292 crank position sensor, 29 4 knock sensor, 296 throttle motor, 297 current sensor, 298 accelerator opening sensor, 302 water temperature sensor, 310 control device, 320 HV_ECU, 321 required torque determining unit, 322 multiplying unit, 323 adding unit, 324 driving force distribution determining unit, 351 Overcurrent detection count counter, 352 release processing counter, 353A upper limit value designation count counter, 353B lower limit value designation count counter, 354 command value setting unit, M1, M3 map.

Claims (8)

A control device for an internal combustion engine mounted on a vehicle,
A setting unit for setting a power command value for the internal combustion engine based on the state of the vehicle;
A control unit for controlling the internal combustion engine according to the power command value,
When the hunting of the power command value occurs, the control unit sets a fixed value instead of the power command value so that the power output from the internal combustion engine becomes the fixed value. A control device for an internal combustion engine that controls the engine. The control device further includes a monitoring unit that monitors the state of the internal combustion engine,
2. The control device for an internal combustion engine according to claim 1, wherein the control unit determines whether hunting of the power command value occurs based on a monitoring result from the monitoring unit and the power command value. . The internal combustion engine has a throttle valve that adjusts its intake air amount,
The control device further includes a motor that drives the throttle valve to change the opening of the throttle valve,
The control device for an internal combustion engine according to claim 2, wherein the monitoring unit monitors a motor current flowing through the motor.   The control unit, when the motor current changes according to the power command value, and the state where the peak value of the motor current exceeds the value corresponding to the power command value continues for a predetermined period. 4. The control apparatus for an internal combustion engine according to claim 3, wherein it is determined that hunting of the power command value has occurred.   When the hunting of the power command value occurs, the control unit acquires an upper limit value and a lower limit value in a fluctuation range of the power command value, and sets one of the upper limit value and the lower limit value as the fixed value. The control apparatus for an internal combustion engine according to claim 1, wherein   The control unit sets one of the upper limit value and the lower limit value to the fixed value, and sets the other of the upper limit value and the lower limit value to the fixed value after a predetermined period has elapsed. The control apparatus of the internal combustion engine described in 1.   The control unit terminates the control of the internal combustion engine based on the fixed value when the power command value is larger than the upper limit value, and controls the internal combustion engine based on the power command value. Item 6. The control device for an internal combustion engine according to Item 5. The internal combustion engine;
A vehicle comprising the control device according to claim 1.

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