JP5018162B2 - VEHICLE CONTROL DEVICE, CONTROL METHOD, PROGRAM FOR MAKING THE METHOD TO COMPUTER COMPUTER, AND RECORDING MEDIUM CONTAINING THE PROGRAM - Google Patents

Description

  The present invention relates to control of a vehicle that uses an internal combustion engine and a rotating electrical machine as a drive source, and more particularly, to a technology that suppresses deterioration of emissions by starting control of an air-fuel ratio at an appropriate time when the internal combustion engine is started.

  2. Description of the Related Art Conventionally, in an internal combustion engine of a vehicle, fuel from a fuel system is mixed with air sucked from an intake system, the air-fuel mixture is combusted in a combustion chamber, and exhaust gas is discharged from an exhaust system. The operation state of the internal combustion engine is controlled based on detection signals from the intake system, the fuel system, and the exhaust system.

  In such an internal combustion engine, the air-fuel ratio (air mixture) is feedback-controlled to the stoichiometric air-fuel ratio by a feedback learning value based on an output signal from an exhaust sensor provided in an exhaust system.

  In recent years, a hybrid vehicle using an internal combustion engine and a rotating electrical machine as a drive source has attracted attention as one of countermeasures for environmental problems. In an internal combustion engine mounted on a hybrid vehicle, an intermittent operation that repeats starting and stopping according to the traveling state of the vehicle is performed, so that emission may be deteriorated during feedback control of the air-fuel ratio at the time of starting. .

  In response to such a problem, for example, Japanese Patent Laid-Open No. 2001-289101 (Patent Document 1) discloses an air-fuel ratio control method for an internal combustion engine that eliminates an increase in emissions. The air-fuel ratio control method includes an internal combustion engine and an electric rotating machine, and uses a power source for a hybrid vehicle that starts the internal combustion engine using the electric rotating machine as a starting motor for the internal combustion engine. The air-fuel ratio is feedback-controlled so that the air-fuel ratio becomes the target air-fuel ratio according to the output of the exhaust sensor provided in the engine, and the air-fuel ratio feedback control is prohibited until a predetermined time has elapsed since the start of the internal combustion engine. It is characterized by that. In particular, in the air-fuel ratio control method disclosed in the above publication, the arrival time is estimated until the combustion gas at the first explosion reaches the exhaust sensor of the exhaust system.

According to the air-fuel ratio control method disclosed in the above publication, feedback control is not started until the combustion gas immediately after starting, that is, the combustion gas at the first explosion reaches the exhaust sensor of the exhaust system, and the output of the exhaust sensor Therefore, the difference between the air-fuel ratio based on the above and the air-fuel ratio in actual combustion does not occur, and an increase in emission can be prevented.
JP 2001-289101 A

  However, in the exhaust sensor, there may be a response delay from when the exhaust gas contacts the detection element constituting the exhaust sensor due to the manufacturing process or other factors until the exhaust sensor outputs a signal corresponding to the air-fuel ratio. is there. Therefore, when the internal combustion engine is started, when the fuel is injected in an increased amount, the air-fuel ratio feedback control is performed until the signal output from the exhaust sensor converges. There is a problem that emissions will deteriorate. In the air-fuel ratio control method disclosed in the above-mentioned publication, since the response delay of the exhaust sensor is not taken into consideration at all, the above-described problem cannot be solved.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to control emissions by controlling the air-fuel ratio based on the responsiveness of the signal output according to the contact between the exhaust gas and the detection element. It is to provide a vehicle control device, a control method, a program for realizing the method by a computer, and a recording medium on which the program is recorded.

  A vehicle control apparatus according to a first aspect of the present invention is a vehicle control apparatus that uses an internal combustion engine and a rotating electric machine as drive sources. The control device includes a means for outputting a signal corresponding to the air-fuel ratio of the internal combustion engine when the exhaust gas of the internal combustion engine contacts the detection element, and a response of a signal output corresponding to the contact between the exhaust gas and the detection element. A calculation means for calculating the level of the property, a setting means for setting a waiting time from the start of the internal combustion engine to the start of control of the air-fuel ratio according to the calculated level, Control means for starting control of the air-fuel ratio so that the air-fuel ratio corresponding to the output signal becomes a target air-fuel ratio set based on the state of the internal combustion engine after the standby time has elapsed from the start. including. The vehicle control method according to the eighth invention has the same configuration as the vehicle control device according to the first invention.

  According to the first aspect of the invention, by setting the standby time according to the level of responsiveness of the signal output according to the contact between the exhaust gas and the detection element, the fuel is injected in an increased amount after the internal combustion engine is started. Even in this case, since the air-fuel ratio feedback control can be stopped until the standby time elapses, that is, until the change in the signal corresponding to the air-fuel ratio converges, the emission deterioration due to the deterioration of the air-fuel ratio control accuracy. Can be suppressed. In addition, after the standby time has elapsed, the emission deterioration can be suppressed by performing feedback control so that the air-fuel ratio becomes the target air-fuel ratio (for example, the theoretical air-fuel ratio). Therefore, it is possible to provide a vehicle control device and control method that suppress the deterioration of emission by controlling the air-fuel ratio based on the response of the signal output according to the contact between the exhaust gas and the detection element.

  In the vehicle control apparatus according to the second aspect of the invention, in addition to the configuration of the first aspect of the invention, the calculating means shifts the air-fuel ratio state of the internal combustion engine from the rich side to the lean side during startup of the internal combustion engine. Means for calculating the level of responsiveness based on the trajectory length of the change in the output signal during a predetermined period when the fuel is injected. A vehicle control method according to a ninth aspect has the same configuration as the vehicle control apparatus according to the second aspect.

  According to the second invention, for example, when the trajectory length is shorter than the trajectory length at the normal responsiveness level, it is determined that a response delay occurs in the signal output with respect to the change in the air-fuel ratio. be able to.

  In the vehicle control apparatus according to the third invention, in addition to the configuration of the first or second invention, the setting means includes means for setting the standby time to be longer as the calculated level is lower. . A vehicle control method according to a tenth invention has the same configuration as the vehicle control device according to the third invention.

  According to the third aspect of the invention, the lower the calculated level, the longer the period until the fluctuation of the air-fuel ratio corresponding to the output signal converges at the start of the internal combustion engine. Therefore, by setting the standby time to be long, execution of air-fuel ratio feedback control can be suppressed until the fluctuation of the air-fuel ratio converges. Therefore, it is possible to suppress the deterioration of emissions.

  In the vehicle control device according to the fourth aspect of the invention, in addition to the configuration of the first or second aspect of the invention, when the calculated level is equal to or lower than the predetermined level, the setting means is more than the predetermined level. Means for setting a predetermined waiting time that is longer than the waiting time set when it is large is included. A vehicle control method according to an eleventh invention has the same configuration as the vehicle control device according to the fourth invention.

  According to the fourth aspect of the invention, when the calculated level becomes equal to or lower than a predetermined level, the period until the fluctuation of the air-fuel ratio corresponding to the output signal converges at the start of the internal combustion engine. Therefore, by setting the standby time to be long, execution of air-fuel ratio feedback control can be suppressed until the fluctuation of the air-fuel ratio converges. Therefore, it is possible to suppress the deterioration of emissions.

  In the vehicle control apparatus according to the fifth aspect of the invention, in addition to the configuration of any one of the first to fourth aspects, the control means is provided after the elapse of the standby time set when the internal combustion engine is started from the stopped state. Means for initiating control of the air-fuel ratio. A vehicle control method according to a twelfth aspect of the invention has the same configuration as the vehicle control apparatus according to the fifth aspect of the invention.

  According to the fifth invention, when the standby time is set, the control of the air-fuel ratio is started after the standby time set when the internal combustion engine is started from the stopped state. Thereby, even when the level of responsiveness is lowered, it is possible to suppress the execution of air-fuel ratio feedback control until the fluctuation of the air-fuel ratio converges. Therefore, it is possible to suppress the deterioration of emissions.

  In the vehicle control apparatus according to the sixth aspect of the invention, in addition to the configuration of any one of the first to fifth aspects, the control means is an empty space corresponding to the output signal after the standby time has elapsed. Means for starting control of the air-fuel ratio is included when the variation amount of the fuel ratio is within a predetermined range. A vehicle control method according to a thirteenth aspect has the same configuration as the vehicle control apparatus according to the sixth aspect.

  According to the sixth aspect of the present invention, the control of the air-fuel ratio is started when the standby time has elapsed and the variation amount of the air-fuel ratio corresponding to the output signal is within a predetermined range. Thereby, when the fluctuation of the air-fuel ratio has converged even after the standby time has elapsed, the deterioration of the emission can be suppressed by further delaying the control of the air-fuel ratio.

  In the vehicle control apparatus according to the seventh aspect of the invention, in addition to the configuration of any one of the first to sixth aspects, the vehicle is connected to the output shaft of the internal combustion engine and generates electric power based on the power of the internal combustion engine. 1 rotating electrical machine and a power split mechanism for transmitting the power of the internal combustion engine to the wheel shaft of the vehicle. The power split mechanism splits the input power of the internal combustion engine into driving force to the wheel shaft or power to the first rotating electrical machine. Between the power split mechanism and the wheel shaft, a second rotating electrical machine that provides driving force to the wheel shaft is provided. A vehicle control method according to a fourteenth aspect of the invention has the same configuration as the vehicle control device according to the seventh aspect of the invention.

  According to the seventh invention, by applying the present invention to a vehicle having a drive system in which the internal combustion engine, the first rotating electrical machine, and the second rotating electrical machine are respectively connected via a power split mechanism, Since the standby time is appropriately set for each intermittent start, it is possible to suppress the deterioration of emissions.

  A program according to the fifteenth invention is a program for realizing the control method according to any of the eighth to fourteenth inventions by a computer, and the recording medium according to the sixteenth invention is any one of the eighth to fourteenth inventions. It is the medium which recorded the program which implement | achieves the control method which concerns on this invention with a computer.

  According to the fifteenth or sixteenth invention, the control method according to any of the eighth to fourteenth inventions can be realized using a computer (which may be general purpose or dedicated).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

<First Embodiment>
A control block diagram of a hybrid vehicle to which a control device according to an embodiment of the present invention is applied will be described with reference to FIG.

  The hybrid vehicle includes an internal combustion engine (hereinafter simply referred to as an engine) 120 such as, for example, a gasoline engine or a diesel engine, and a motor generator (MG) 140 that is a rotating electric machine as drive sources. In FIG. 1, for convenience of explanation, the motor generator 140 is expressed as a motor 140A and a generator 140B (or a motor generator 140B). However, depending on the traveling state of the hybrid vehicle, the motor 140A functions as a generator, The generator 140B functions as a motor.

  In the intake passage 122 of the engine 120, an air cleaner 122A that captures dust of intake air, an air flow meter 122B that detects the amount of air sucked into the engine 120 through the air cleaner 122A, and an amount of air sucked into the engine 120 are adjusted. For this purpose, an electronic throttle valve 122C is provided. The electronic throttle valve 122C is provided with a throttle position sensor. The engine ECU 280 receives the intake air amount detected by the air flow meter 122B, the opening degree of the electronic throttle valve 122C detected by the throttle position sensor, and the like.

  Engine 120 is provided with a plurality of cylinders and a fuel injection device 130 that injects fuel into each cylinder. The fuel injection device 130 injects an appropriate amount of fuel to each cylinder at an appropriate time based on a fuel injection control signal from the engine ECU 280.

  Further, in the exhaust passage 124 of the engine 120, a three-way catalytic converter 124B, an air-fuel ratio sensor 124A for detecting an air-fuel ratio (A / F) in the exhaust gas introduced into the three-way catalytic converter 124B, and a three-way catalytic converter 124B. A catalyst temperature sensor 124C for detecting the temperature of the catalyst and a silencer 124D are provided. An engine ECU (Electronic Control Unit) 280 includes an air-fuel ratio of exhaust gas introduced into the three-way catalytic converter 124B detected by the air-fuel ratio sensor 124A, a temperature of the three-way catalytic converter 124B detected by the catalyst temperature sensor 124C, and the like. Is entered.

  Air-fuel ratio sensor 124A is a full-range air-fuel ratio sensor (linear air-fuel ratio sensor) that generates an output voltage proportional to the air-fuel ratio of the air-fuel mixture burned by engine 120. In the present embodiment, air-fuel ratio sensor 124 </ b> A has a detection element, and outputs a signal corresponding to the air-fuel ratio of engine 120 by contacting exhaust gas of engine 120 with the detection element. As the air-fuel ratio sensor 124A, an O2 sensor that detects whether the air-fuel ratio of the air-fuel mixture burned by the engine 120 is rich or lean with respect to the stoichiometric air-fuel ratio may be used. .

  Engine ECU 280 also receives a signal indicating the engine cooling water temperature from water temperature detection sensor 360 that detects the temperature of the cooling water of engine 120. A crank position sensor 380 is provided on the output shaft of the engine 120, and a signal indicating the rotation speed of the output shaft is input from the crank position sensor 380 to the engine ECU 280.

  In addition to this, the hybrid vehicle transmits a power generated by the engine 120 and the motor generator 140 to the drive wheels 160, and a reduction gear 180 that transmits the drive of the drive wheels 160 to the engine 120 and the motor generator 140, and the engine 120. Power split mechanism (for example, planetary gear mechanism) 200 that distributes the generated power to two paths of drive wheel 160 and generator 140B, travel battery 220 that charges power for driving motor generator 140, and travel Inverter 240 that performs current control while converting the direct current of battery 220 for the motor and the alternating current of motor 140A and generator 140B, and a battery control unit (hereinafter referred to as a battery ECU) 260 that manages and controls the charge / discharge state of battery for traveling 220 , Operating state of engine 120 The hybrid vehicle is the most efficient by controlling and controlling the engine ECU 280 to be controlled, the MG_ECU 300 for controlling the motor generator 140, the battery ECU 260, the inverter 240, etc., and the battery ECU 260, the engine ECU 280, the MG_ECU 300, etc. according to the state of the hybrid vehicle. HV_ECU 320 etc. which control the whole hybrid system so that it can operate well are included. In addition, a power storage mechanism such as a capacitor may be used instead of the traveling battery.

  In the present embodiment, converter 242 is provided between battery for traveling 220 and inverter 240. This is because the rated voltage of the traveling battery 220 is lower than the rated voltage of the motor 140A or the motor generator 140B, and therefore when the power is supplied from the traveling battery 220 to the motor 140A or the motor generator 140B, the converter 242 boosts the power. To do. This converter 242 has a built-in smoothing capacitor, and when the converter 242 performs a boosting operation, electric charge is stored in this smoothing capacitor.

  In FIG. 1, each ECU is configured separately, but may be configured as an ECU in which two or more ECUs are integrated (for example, MG_ECU 300 and HV_ECU 320, as shown by a dotted line in FIG. 1). An example is an integrated ECU).

  The driver's seat is provided with an accelerator pedal (not shown), and an accelerator position sensor (not shown) detects the amount of depression of the accelerator pedal. The accelerator position sensor outputs a signal indicating the amount of depression of the accelerator pedal to the HV_ECU 320. The HV_ECU 320 controls the output of the engine 120 or the power generation amount via the motor 140A, the generator 140B, and the engine ECU 280 according to the required driving force corresponding to the depression amount.

  Furthermore, the vehicle speed sensor 330 is a sensor that detects a physical quantity related to the speed of the vehicle. The “physical quantity related to the vehicle speed” may be, for example, the rotational speed of the wheel shaft or the rotational speed of the output shaft of the transmission. The vehicle speed sensor 330 transmits the detected physical quantity to the engine ECU 280.

  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.

  In a hybrid vehicle equipped with a hybrid system as shown in FIG. 1, the hybrid vehicle travels only by the motor 140 </ b> A of the motor generator 140 when the engine 120 is inefficient, such as when starting or running at a low speed. During normal travel, for example, the power split mechanism 200 divides the power of the engine 120 into two paths, and on the other hand, the drive wheels 160 are directly driven, and on the other hand, the generator 140B is driven to generate power. At this time, the motor 140A is driven by the generated electric power to assist driving of the driving wheels 160. Further, at the time of 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 to 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 amount of charge of traveling battery 220 decreases 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 amount of charge for traveling battery 220. Of course, there is a case where control is performed to increase the driving force of the engine 120 as necessary even during low-speed traveling. For example, it is necessary to charge the traveling battery 220 as described above, to drive an auxiliary machine such as an air conditioner, or to raise the temperature of the cooling water of the engine 120 to a predetermined temperature.

  Furthermore, in a hybrid vehicle equipped with a hybrid system as shown in FIG. 1, engine 120 is stopped in order to improve fuel consumption depending on the driving state of the vehicle and the state of traveling battery 220. And after that, the driving | running state of the vehicle and the state of the battery 220 for driving | running | working are detected, and the engine 120 is restarted. In this way, the engine 120 is intermittently operated, and in a conventional vehicle (a vehicle equipped with only an engine), when the ignition switch is turned to the START position and the engine is started, the ignition switch is switched from the ON position to the ACC position. Or it is different in that the engine does not stop until it is in the OFF position.

  In the vehicle having the above-described configuration, the present invention is calculated in that the engine ECU 280 calculates the level of responsiveness of the signal output according to the contact between the exhaust gas and the detection element included in the air-fuel ratio sensor 124A. In accordance with the level of responsiveness, after setting the standby time from the start of the engine 120 to the start of control of the air-fuel ratio of the engine 120, and after the standby time has elapsed since the start of the engine 120, It is characterized in that the control of the air-fuel ratio is started so that the air-fuel ratio detected by the air-fuel ratio sensor 124A becomes the target air-fuel ratio (for example, the theoretical air-fuel ratio) set based on the state of the engine 120.

  FIG. 2 shows a functional block diagram of engine ECU 280 which is a vehicle control apparatus according to the present embodiment.

  Engine ECU 280 includes an input interface (hereinafter referred to as an input I / F) 350, an arithmetic processing unit 400, a storage unit 500, and an output interface (hereinafter referred to as an output I / F) 600.

  The input I / F 300 receives the air-fuel ratio signal from the air-fuel ratio sensor 124 </ b> A and the engine speed signal from the crank position sensor 380, and transmits them to the arithmetic processing unit 400.

  The arithmetic processing unit 400 includes a start determination unit (1) 402, a level calculation unit 404, a standby time setting unit 406, a start determination unit (2) 408, and a feedback (hereinafter referred to as F / B) control unit. 410.

  The start determination unit (1) 402 determines whether or not the engine 120 is starting. The start determination unit (1) 402 determines, for example, that the engine 120 is being started when the rotational speed of the engine 120 detected by the crank position sensor 380 is equal to or higher than a predetermined rotational speed. Also good. The start determination unit (1) 402 may turn on the start determination flag (1) when the engine 120 is starting.

  The level calculation unit 404 calculates the responsiveness level of the air-fuel ratio sensor 124A corresponding to the time from when the exhaust gas contacts the detection element of the air-fuel ratio sensor 124A until the signal corresponding to the exhaust gas that has contacted is output. calculate.

  Specifically, the level calculation unit 404 outputs the air-fuel ratio sensor 124A during a predetermined period when fuel is injected so that the air-fuel ratio shifts from the rich side to the lean side during the start of the engine 120. The level of responsiveness is calculated based on the trajectory length of the signal change. For example, the level calculation unit 404 calculates the level of responsiveness based on the locus length of the change in the output signal of the air-fuel ratio sensor 124A for one cycle of movement that changes from rich to lean.

  In the present embodiment, for example, the trajectory length of the change in the output signal in the air-fuel ratio sensor 124A having normal responsiveness is used as a reference level, and the trajectory length is adjusted to the shorter trajectory length side and the longer trajectory length side. Set multiple levels. The level calculation unit 404 indicates which of the plurality of levels the locus length of the change in the output signal of the air-fuel ratio sensor 124A when the fuel is injected so that the air-fuel ratio is shifted from the rich side to the lean side. To determine the level of responsiveness. The method for calculating the level of responsiveness based on the trajectory length is not particularly limited to the above-described method. For example, the level of responsiveness corresponding to the trajectory length may be specified using a map, a table, a mathematical expression, or the like. The level calculation unit 404 may calculate the level of responsiveness when the start determination flag (1) is on.

  The standby time setting unit 402 sets a standby time from when the engine 120 is started until the air-fuel ratio feedback control is started according to the calculated level of responsiveness. For example, a map, a table, a mathematical expression or the like indicating the relationship between the level of responsiveness and the standby time is stored in advance in the storage unit 500, and the standby time setting unit 402 stores the calculated level of responsiveness and the storage unit 500. The waiting time is set according to the map or the like stored in. For example, the standby time setting unit 402 sets the standby time to increase as the level of responsiveness decreases. The standby time is the time from when the engine 120 is started until the fluctuation of the signal output from the air-fuel ratio sensor 124A converges according to the level of responsiveness. Pre-adapted accordingly.

  Start determination unit (2) 408 determines whether engine 120 is started from a stopped state. For example, the start determination unit (2) 408 starts the engine 120 from a stopped state when the rotation speed of the engine 120 detected by the crank position sensor 380 is increased from approximately zero to a predetermined rotation speed or more. Judge that. Note that the start determination unit (2) 408 may turn on the start determination flag (2) when it is determined that the engine 120 has been started from a stopped state. In the present embodiment, it has been described that start determination of engine 120 is performed based on the number of revolutions of engine 120, but the present invention is not particularly limited to this.

  When the engine 120 is started from a stopped state, the F / B control unit 410 is configured such that the air-fuel ratio detected by the air-fuel ratio sensor 124A is set based on the state of the engine 120 after the standby time has elapsed since starting. The air-fuel ratio is feedback controlled so that

  In the present embodiment, the “target air-fuel ratio” will be described as a theoretical air-fuel ratio. The F / B control unit 410 generates a fuel injection control signal based on the difference between the stoichiometric air-fuel ratio and the air-fuel ratio detected by the air-fuel ratio sensor 124A, and transmits it to the fuel injection device 130 via the output I / F 600. To do.

  Preferably, the F / B control unit 410 has an air-fuel ratio fluctuation amount (for example, fluctuation amount per unit time) detected by the air-fuel ratio sensor 124 after the standby time has elapsed since the start. When it falls within a predetermined range, it is desirable to execute feedback control of the air-fuel ratio. Since air-fuel ratio feedback control is a well-known technique, a detailed description thereof will not be given. The predetermined range is often adapted by experiment or the like as long as it does not affect the feedback control.

  In the present embodiment, start determination unit (1) 402, level calculation unit 404, standby time setting unit 406, start determination unit (2) 408, and F / B control unit 410 are all the same. Although the description will be made assuming that a CPU (Central Processing Unit) that is the arithmetic processing unit 400 executes a program stored in the storage unit 500 and functions as software, it may be realized by hardware. Good. Such a program is recorded on a storage medium and mounted on the vehicle.

  Various information, programs, threshold values, maps, and the like are stored in the storage unit 500, and data is read or stored from the arithmetic processing unit 400 as necessary.

  Hereinafter, with reference to FIG. 3, a control structure of a program executed by engine ECU 280 which is the vehicle control apparatus according to the present embodiment will be described.

  In step (hereinafter, step is described as S) 100, engine ECU 280 determines whether engine 120 is being started or not. If engine 120 is starting (YES in S100), the process proceeds to S102. If not (NO in S100), the process returns to S100.

  In S102, engine ECU 280 calculates the level of responsiveness. In S104, engine ECU 280 sets a standby time according to the calculated level of responsiveness.

  In S106, engine ECU 280 determines whether or not engine 120 has been started from a stopped state. If engine 120 is started from a stopped state (YES in S106), the process proceeds to S108. If not (NO in S106), the process returns to S106.

  In S108, engine ECU 280 performs F / B control after the set standby time has elapsed since engine 120 started. Engine ECU 280 determines whether or not the standby time has elapsed based on the time measured by a timer (not shown) after engine 120 is started.

  The operation of engine ECU 280, which is the vehicle control apparatus according to the present embodiment, based on the above-described structure and flowchart will be described with reference to FIG.

  For example, it is assumed that the vehicle engine 120 is stopped. At time T (0), engine ECU 280 starts engine 120 in response to a start request based on the state of the vehicle such as the charge capacity of the battery. The air-fuel ratio F / B control is performed at time T (1) after the standby time Ta has elapsed since the engine 120 was started. At this time, since engine 120 is being started (YES in S100), the level of responsiveness of air-fuel ratio sensor 124A is calculated at time T (2) (S102). Further, the waiting time Ta is updated to the waiting time Tb according to the calculated level of responsiveness (S104).

  When there is a stop request based on the state of the vehicle at time T (3), engine ECU 280 stops engine 120. If there is a start request based on the state of the vehicle again at time T (4), engine ECU 280 starts engine 120. At time T (5), engine ECU 280 is starting from the stopped state of engine 120 (YES in S106), and therefore, air-fuel ratio F / B control is performed when waiting time Tb has elapsed since engine 120 was started. Is executed (S108).

  As described above, according to the control device for a vehicle according to the present embodiment, the standby time is set according to the level of responsiveness of the signal output according to the contact between the exhaust gas and the detection element. Even when the fuel is injected in an increased amount after starting, the air-fuel ratio feedback control can be stopped until the standby time elapses, that is, until the change in the signal corresponding to the air-fuel ratio converges. It is possible to suppress the deterioration of the emission due to the deterioration of the control accuracy of the air-fuel ratio. Further, after the standby time has elapsed, the deterioration of the emission can be suppressed by controlling the air-fuel ratio to be the target air-fuel ratio (for example, the theoretical air-fuel ratio). Therefore, a vehicle control device, a control method, and a method thereof that suppress deterioration of emissions by controlling the air-fuel ratio based on the responsiveness of the signal output according to the contact between the exhaust gas and the detection element are realized by a computer. A program and a recording medium on which the program is recorded can be provided.

  Further, when the trajectory length is shorter than the trajectory length at the normal level of responsiveness, it can be determined that there is a response delay in the signal output with respect to fluctuations in the air-fuel ratio.

  Furthermore, the lower the calculated level, the longer the period until the fluctuation of the air-fuel ratio corresponding to the output signal converges at the start of the internal combustion engine. Therefore, by setting the standby time to be long, execution of air-fuel ratio feedback control can be suppressed until the fluctuation of the air-fuel ratio converges. Therefore, it is possible to suppress the deterioration of emissions.

  Then, after the standby time has elapsed, the air-fuel ratio control is started when the fluctuation amount of the air-fuel ratio corresponding to the output signal is within a predetermined range. Thereby, when the fluctuation of the air-fuel ratio has converged even after the standby time has elapsed, the deterioration of the emission can be suppressed by further delaying the control of the air-fuel ratio.

  And in a vehicle where the engine is idle-stopped, such as a hybrid vehicle, the engine is repeatedly intermittently started. Therefore, the deterioration of the emission can be suppressed by appropriately setting the standby time for each intermittent start. In the present embodiment, the case where the present invention is applied to a hybrid vehicle has been described. For example, a vehicle using an engine as a drive source, and when a predetermined stop condition is satisfied, the engine is stopped. You may make it apply to the vehicle by which the idling stop system is mounted.

<Second Embodiment>
Hereinafter, the vehicle control apparatus according to the second embodiment will be described. The vehicle control device according to the present embodiment differs from the configuration of the vehicle control device according to the first embodiment described above in the control structure of a program executed by engine ECU 280. The rest of the configuration is the same as the configuration of the vehicle control device according to the first embodiment described above. They are given the same reference numerals. Their functions are the same. Therefore, detailed description thereof will not be repeated here.

  In the present embodiment, when engine ECU 280 sets the standby time, if the calculated level of responsiveness falls below a predetermined level, the standby is set when the level is higher than the predetermined level. It is characterized in that a predetermined standby time longer than the time is set. The “predetermined level” may be a level at which it is possible to determine that the responsiveness of the signal output of the air-fuel ratio sensor is abnormal, and is adapted by, for example, experiments.

  Hereinafter, with reference to FIG. 5, a control structure of a program executed by engine ECU 280 which is the vehicle control apparatus according to the present embodiment will be described.

  In the flowchart shown in FIG. 5, the same steps as those in the flowchart shown in FIG. 3 are given the same step numbers. The processing for them is the same. Therefore, detailed description thereof will not be repeated here.

  When the responsiveness reduction level is calculated in S102, in S204, engine ECU 280 determines whether or not the calculated level is equal to or lower than a predetermined level. If the calculated level is equal to or lower than a predetermined level (YES in S204), the process proceeds to S206. If not (NO in S204), the process proceeds to S208.

  In S206, engine ECU 280 turns on the abnormality determination flag. In S208, engine ECU 280 turns off the abnormality determination flag.

  In S210, engine ECU 280 determines whether or not engine 120 has been started from a stopped state. If engine 120 is started from a stopped state (YES in S210), the process proceeds to S212. If not (NO in S210), the process returns to S210.

  In S212, engine ECU 280 sets a standby time according to the on / off state of the abnormality determination flag, and executes F / B control after the set standby time has elapsed after engine 120 is started. To do. Specifically, engine ECU 280 sets a predetermined standby time set as a normal value when abnormality determination flag is OFF. When the abnormality determination flag is on, engine ECU 280 sets a predetermined standby time that is larger than the normal value. The predetermined waiting time set when the abnormality determination flag is on is not particularly limited. For example, the waiting time is changed a plurality of times to experiment with a time when the degree of deterioration of emission is low. And so on.

  The operation of engine ECU 280, which is the vehicle control apparatus according to the present embodiment, based on the above-described structure and flowchart will be described.

  For example, it is assumed that the vehicle engine 120 is stopped. The engine ECU 280 starts the engine 120 in response to a start request based on the state of the vehicle such as the battery charge capacity. The air-fuel ratio F / B control is performed after the standby time Ta has elapsed since the engine 120 was started. At this time, since engine 120 is starting (YES in S100), the level of responsiveness of air-fuel ratio sensor 124A is calculated (S102). Further, when the calculated level of responsiveness is an abnormal level equal to or lower than a predetermined level, the abnormality determination flag is turned on (S206).

  If there is a stop request based on the state of the vehicle, engine ECU 280 stops engine 120. Then, when there is a start request again based on the state of the vehicle, engine ECU 280 starts engine 120. The engine ECU 280 is started from the stopped state of the engine 120 (YES in S210), and since the abnormality determination flag is turned on, a standby time Tb longer than the standby time Ta has elapsed since the engine 120 started. At this point, air-fuel ratio F / B control is executed (S212).

  If the calculated response level is a normal level larger than a predetermined level (NO in S204), the abnormality determination flag is turned off (S208). Therefore, when the engine 120 is started from a stopped state (YES in S210), the abnormality determination flag is turned off, and therefore, when the standby time Ta has elapsed after the engine 120 has started, the air-fuel ratio F / B Execute control.

  As described above, according to the control apparatus for a vehicle according to the present embodiment, when the calculated level becomes equal to or lower than a predetermined level, the fluctuation of the air-fuel ratio corresponding to the output signal is started when the engine is started. The period until the convergence becomes longer. Therefore, by setting the standby time to be long, execution of air-fuel ratio feedback control can be suppressed until the fluctuation of the air-fuel ratio converges. Therefore, it is possible to suppress the deterioration of emissions.

  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.

It is a control block diagram of the hybrid vehicle which concerns on 1st Embodiment. It is a functional block diagram which shows the structure of engine ECU. It is a flowchart which shows the control structure of the program performed with engine ECU which is the control apparatus of the vehicle which concerns on 1st Embodiment. It is a timing chart which shows operation of engine ECU which is a control device of vehicles concerning a 1st embodiment. It is a flowchart which shows the control structure of the program performed by engine ECU which is a control apparatus of the vehicle which concerns on 2nd Embodiment.

Explanation of symbols

  120 engine, 122 intake passage, 122A air cleaner, 122B air flow meter, 122C electronic throttle valve, 124 exhaust passage, 124A air-fuel ratio sensor, 124B three-way catalytic converter, 124C catalyst temperature sensor, 124D silencer, 130 fuel injection device, 140 motor Generator, 140A Motor, 140B Generator, 160 Drive Wheel, 180 Reducer, 200 Power Dividing Mechanism, 220 Traveling Battery, 240 Inverter, 242 Converter, 260 Battery ECU, 280 Engine ECU, 300 MG_ECU, 320 HV_ECU, 330 Vehicle Speed Sensor, 350 Input I / F, 360 Water temperature detection sensor, 380 Crank position sensor, 400 Arithmetic processing unit, 402, 408 Start determination unit, 40 4 level calculation unit, 406 standby time setting unit, 410 F / B control unit, 500 storage unit, 600 output I / F.

Claims (14)

A control device for a vehicle using an internal combustion engine and a rotating electric machine as drive sources,
Means for outputting a signal corresponding to the air-fuel ratio of the internal combustion engine when the exhaust gas of the internal combustion engine comes into contact with a detection element;
A calculating means for calculating the level of responsiveness of the output of the signal corresponding to the contact between the exhaust gas and the detection element,
Setting means for setting a standby time from the start of the internal combustion engine to the start of control of the air-fuel ratio according to the calculated level;
Control of the air-fuel ratio so that the air-fuel ratio corresponding to the output signal becomes a target air-fuel ratio set based on the state of the internal combustion engine after the standby time has elapsed since the internal combustion engine started. look including a control means for initiating,
The calculating means is provided when the locus length of the change in the output signal in a predetermined period when the fuel is injected so that the state of the air-fuel ratio of the internal combustion engine shifts from the rich side to the lean side is short. Includes means for calculating the level of responsiveness during operation of the internal combustion engine such that the level of responsiveness is low compared to when the trajectory length is long,
The setting means is configured such that the standby time set when the calculated level is equal to or lower than a predetermined level is longer than the standby time set when the calculated level is larger than the predetermined level. A control apparatus for a vehicle, including means for setting the standby time . The vehicle control device according to claim 1 , wherein the setting unit includes a unit configured to set the standby time to be longer as the calculated level is lower. 3. The vehicle control according to claim 1, wherein the control means includes means for starting control of the air-fuel ratio after elapse of the set standby time when the internal combustion engine is started from a stopped state. 4. apparatus. The control means is for starting the control of the air-fuel ratio when the waiting time has elapsed and the variation amount of the air-fuel ratio corresponding to the output signal is within a predetermined range. comprising means, the control device for a vehicle according to any one of claims 1-3. The vehicle is connected to an output shaft of the internal combustion engine, and includes a first rotating electrical machine that generates electric power based on the power of the internal combustion engine, and a power split mechanism that transmits the power of the internal combustion engine to the wheel shaft of the vehicle. The power split mechanism splits the input power of the internal combustion engine into drive power to the wheel shaft or power to the first rotating electrical machine, and between the power split mechanism and the wheel shaft. the second rotating electric machine for applying a driving force to the wheel shaft are provided, the control apparatus for a vehicle according to any one of claims 1-4. The waiting time is a period from when the internal combustion engine is started until a change in the air-fuel ratio is converged, in which a variation amount of the air-fuel ratio corresponding to the output of the signal falls within a predetermined range. Item 2. The vehicle control device according to Item 1. A method for controlling a vehicle using an internal combustion engine and a rotating electric machine as drive sources,
Outputting a signal corresponding to the air-fuel ratio of the internal combustion engine when the exhaust gas of the internal combustion engine comes into contact with a detection element;
A calculation step of calculating the level of responsiveness of the output of the signal corresponding to the contact between the exhaust gas and the detection element,
A setting step of setting a waiting time from the start of the internal combustion engine to the start of control of the air-fuel ratio according to the calculated level;
Control of the air-fuel ratio so that the air-fuel ratio corresponding to the output signal becomes a target air-fuel ratio set based on the state of the internal combustion engine after the standby time has elapsed since the internal combustion engine started. look including a control step to start,
In the calculating step, during the operation of the internal combustion engine, the output signal of the output signal in a predetermined period when the fuel is injected so that the air-fuel ratio state of the internal combustion engine shifts from the rich side to the lean side. When the change trajectory length is short, including the step of calculating the responsiveness level so that the responsiveness level is lower than when the trajectory length is long,
The setting step is such that the standby time set when the calculated level is equal to or lower than a predetermined level is longer than the standby time set when the predetermined level is larger than the predetermined level. A method for controlling a vehicle, comprising the step of: setting the waiting time at a time . The vehicle control method according to claim 7 , wherein the setting step includes a step of setting the waiting time longer as the calculated level becomes lower. The vehicle control method according to claim 7 or 8 , wherein the control step includes a step of starting control of the air-fuel ratio after the set standby time has elapsed when the internal combustion engine is started from a stopped state. The control step includes the step of starting the control of the air-fuel ratio when the waiting time has elapsed and the variation amount of the air-fuel ratio corresponding to the output signal is within a predetermined range. The vehicle control method according to any one of claims 7 to 9 , further comprising: The vehicle is connected to an output shaft of the internal combustion engine, and includes a first rotating electrical machine that generates electric power based on the power of the internal combustion engine, and a power split mechanism that transmits the power of the internal combustion engine to the wheel shaft of the vehicle. The power split mechanism splits the input power of the internal combustion engine into drive power to the wheel shaft or power to the first rotating electrical machine, and between the power split mechanism and the wheel shaft. the second rotating electric machine for applying a driving force to the wheel shaft are provided, the control method for a vehicle according to any one of claims 7-10. The waiting time is a period from when the internal combustion engine is started until a change in the air-fuel ratio is converged, in which a variation amount of the air-fuel ratio corresponding to the output of the signal falls within a predetermined range. Item 8. The vehicle control method according to Item 7 . Program causes realizing the control method according to the computer in any one of claims 7 to 12. Recording medium for recording a program causing realizing the control method according to the computer in any one of claims 7 to 12.

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