JP2009040234A - Control device of hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To execute the ISC learning control of an intermittently operated engine while protecting a driver against shock and avoiding deterioration of fuel consumption. <P>SOLUTION: An engine ECU executes a program including a step (S1060) for setting an engine stop inhibition flag and operating the engine if the engine is warmed up (YES at S1020), if the vehicle speed is a low speed not higher than a threshold value (YES at S1040), and if the brake is operated (YES at S1050), and a step (S1090) for executing the ISC learning control if an ISC learning requirement such as the stop of the vehicle is met (YES at S1080). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to engine control of a hybrid vehicle equipped with an engine and intermittently operating the engine as necessary, and in particular, accurately performs control amount learning in the engine such as ISC (Idle Speed Control) learning and air-fuel ratio learning. The present invention relates to a control device for a hybrid vehicle.

  In recent years, an engine that operates with the combustion energy of fuel and a motor that operates with electric energy have been provided as a power source when the vehicle travels, and an automatic transmission (power split mechanism is installed between the power source and driving wheels. Hybrid vehicles equipped with the above are put into practical use. In such a hybrid vehicle, for example, by using the engine and the motor properly according to the driving state, it is possible to reduce the fuel consumption amount and the exhaust gas amount while maintaining a predetermined traveling performance. Specifically, an engine running mode in which only the engine is used as a power source, a motor running mode in which the vehicle is run using only the motor as a power source (with the engine stopped), and an engine + motor that runs using both the engine and the motor as power sources. It has a plurality of operation modes with different operating states of the engine and the motor, such as a driving mode, and a power source map or the like that has a predetermined parameter such as a vehicle speed (or a power source rotation speed) and an operation amount of an accelerator is predetermined. Switching is automatically performed according to mode switching conditions. That is, the engine is intermittently operated even when the vehicle is running.

  In such a hybrid vehicle, it is necessary to detect various sensor signals and switch signals, and control to stop the engine and restart the engine again when a predetermined engine stop condition is satisfied. There is (for example, it can be said that such an operating state of the engine is a state of intermittent operation described above). Even in an engine mounted on a hybrid vehicle that repeatedly stops and restarts the engine, learning control of the engine control amount that occurs due to individual differences in the engine and changes over time is performed.

  For example, in the engine, ISC control is performed. This ISC control is control for maintaining the idling speed of the engine at a constant speed. Specifically, the idling speed is controlled by driving the throttle valve of the engine with an actuator and adjusting the air (mixture) flow rate. In this ISC control device, feedback control is performed in order to bring the rotational speed at idling closer to the target value. Thereby, the rotation speed can be kept substantially constant.

  In feedback control, the air flow rate required to maintain the engine idling speed at a constant speed changes depending on factors such as individual differences and changes over time. So-called learning control is performed to reflect and store feedback results. It is. Usually, the initial value of the learning value of the idling air flow rate is set to a larger value in order to avoid engine stall. When learning is not completed, ISC control is performed with this initial value.

  In the hybrid vehicle described above, since the engine is intermittently operated, naturally, the learning control cannot be executed when the engine is not operating. On the other hand, simply giving priority to learning control always prohibits the engine from being stopped and keeps the engine running. Therefore, the engine continues to run against the assumption of the driver, which may cause the driver to feel uncomfortable. .

Japanese Patent Laying-Open No. 2006-266193 (Patent Document 1) discloses a vehicle that can ensure an opportunity to learn a control amount when idling an internal combustion engine without giving a driver a sense of incongruity. This vehicle is a vehicle that can run by driving an internal combustion engine with intermittent operation, and is controlled by an idle control amount learning means that learns a control amount when the internal combustion engine is idle-operated, and an idle control amount learning means. Intermittent learning prohibiting means for prohibiting intermittent operation of the internal combustion engine based on a predetermined operation by the operator until the learning is completed. Preferably, the predetermined operation is an operation that causes the operator to assume the intermittent operation of the internal combustion engine. More preferably, the intermittent operation prohibiting means permits the intermittent operation of the internal combustion engine when the shift operation is performed to the parking position, and prohibits the intermittent operation of the internal combustion engine when the shift operation is performed to a travelable position other than the parking position. To do.
JP 2006-266193 A

  According to Patent Document 1 described above, when it is determined that learning of the idle speed control amount is not completed (unlearned), if the shift position is determined to be the P (parking) position, intermittent engine operation is performed. If it is permitted and it is determined that the shift position is a travelable position (for example, D (drive) position), intermittent operation of the engine is prohibited. When the intermittent operation of the engine is prohibited, the engine is not automatically stopped regardless of whether the automatic stop condition is satisfied. When the learning of the idle speed control amount is not completed, the intermittent operation of the engine is prohibited in this way in order to secure the opportunity for learning the idle speed control amount and complete the learning early. The reason why the intermittent operation of the engine is permitted when the shift position is the P position is that the driver is assumed to stop the engine at the P position, so that the engine operation is continued against the assumption of the driver. This is to prevent the driver from feeling uncomfortable.

  However, in the control disclosed in Patent Document 1 described above, since the intermittent operation of the engine is permitted while the vehicle is stopped, the engine that has been stopped for ISC learning control may start. At this time, the driver feels a start shock of the engine.

  Also, when the engine that has been stopped for ISC learning control is started during deceleration operation with the brake off, the driver feels a start shock of the engine.

  On the other hand, if the learning control enabled condition is satisfied, the engine intermittent operation is prohibited and the engine is continuously operated to complete the learning control, so that the time during which the engine is operating becomes longer and the fuel consumption is deteriorated.

  The present invention has been made in order to solve the above-described problems. The object of the present invention is to perform learning control of a control amount of an internal combustion engine that is intermittently operated without giving a shock to the driver and improving fuel efficiency. It is an object of the present invention to provide a control device for a hybrid vehicle that can be executed while avoiding deterioration.

  The control device according to the first invention controls a hybrid vehicle having an internal combustion engine and a power source other than the internal combustion engine as a travel source of the vehicle. The control device is configured to temporarily stop the internal combustion engine when the vehicle condition satisfies the temporary stop condition, and to control the internal combustion engine so as to restart the internal combustion engine when the restart condition is satisfied; In a driving region where the internal combustion engine is operating stably, learning execution means for executing control amount learning, means for detecting the operating state of the braking device operated by the driver, and vehicle speed When the condition of the detection means for detection and the vehicle in which learning is possible, the braking device operates and the speed is equal to or less than a predetermined speed, the internal combustion engine is temporarily stopped. And prohibiting means.

  According to the first invention, in order to learn the control amount of the internal combustion engine mounted on the hybrid vehicle (ISC learning control), it is assumed that the internal combustion engine is operating. In order to operate the internal combustion engine, a temporary stop of the internal combustion engine is prohibited. However, if the temporary stop of the internal combustion engine is prohibited when the vehicle is stopped or the braking device is not operating, the internal combustion engine is It is restarted and the driver feels a start shock. In addition, ISC learning is possible even when the internal combustion engine is operated by prohibiting the temporary stop of the internal combustion engine when the vehicle is not in a state where learning is possible (for example, before warming up the internal combustion engine) or when the vehicle speed is high. Control (performed when the internal combustion engine is operating stably when the vehicle is stopped) cannot be executed promptly, simply prohibiting the temporary stop of the internal combustion engine and operating the internal combustion engine to deteriorate fuel consumption. Absent. For this reason, the prohibition of temporary stop of the internal combustion engine is a state of the vehicle in which learning is possible (for example, after warming up of the internal combustion engine), and the braking device operates and the speed is equal to or lower than a predetermined speed. This is done when the condition is satisfied. In this way, even if the internal combustion engine that has been stopped because the temporary stop of the internal combustion engine is prohibited is started, the driver feels that the vehicle is running and the driver operates the braking device. The start shock of the internal combustion engine can be reduced. Furthermore, since the vehicle speed is low, the vehicle will soon stop and the ISC learning control can be executed to stop the internal combustion engine. Therefore, the temporary stop prohibition period of the internal combustion engine can be shortened to reduce fuel consumption. Can be suppressed. As a result, there is provided a control device for a hybrid vehicle capable of executing learning control of a control amount of an internal combustion engine that is intermittently operated without giving a shock to the driver and avoiding deterioration of fuel consumption. be able to.

  In the control device according to the second invention, in addition to the configuration of the first invention, the prohibiting means is a state of the vehicle in which the internal combustion engine is warmed up and learning is possible, and the braking device operates and the speed Includes means for prohibiting the temporary stop of the internal combustion engine when satisfying a condition that is less than or equal to a predetermined speed.

  According to the second invention, when the internal combustion engine is warmed up and learning is possible and the vehicle speed is low, temporary stop of the internal combustion engine is prohibited. The ISC learning control of the warmed-up internal combustion engine is promptly executed. Thereby, the prohibition period of the temporary stop of an internal combustion engine can be shortened, and deterioration of fuel consumption can be suppressed.

  In the control device according to the third invention, in addition to the configuration of the first or second invention, the learning execution means includes means for executing learning of the air flow rate for maintaining the idle speed of the internal combustion engine. Including.

  According to the third aspect of the invention, the ISC learning control, which is an example of learning the control amount of the internal combustion engine mounted on the hybrid vehicle, is executed without giving a shock to the driver and avoiding deterioration of fuel consumption. be able to.

  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. The hybrid vehicle described below is not limited as long as the engine intermittently operates according to the state of the vehicle, and the hybrid system is not limited.

  With reference to FIG. 1, the control block diagram of the whole hybrid vehicle including the control apparatus which concerns on embodiment of this invention is demonstrated. The present invention is not limited to the hybrid vehicle shown in FIG. In the present invention, an internal combustion engine such as a gasoline engine (hereinafter referred to as an engine) as a power source may be a drive source for driving a vehicle and a generator drive source. Furthermore, the drive source is an engine and a motor generator, and the vehicle is capable of traveling by the power of the motor generator, and the hybrid is provided with a battery for traveling that may stop the engine during traveling. It may be a vehicle. This battery is a nickel metal hydride battery or a lithium ion battery, and the type thereof is not particularly limited. A capacitor may be used instead of the battery.

  The hybrid vehicle includes an engine 120 and a motor generator (MG) 140. In the following, for convenience of explanation, the motor generator 140 is expressed as a motor generator 140A (or MG (2) 140A) and a motor generator 140B (or MG (1) 140B). Accordingly, motor generator 140A functions as a generator, or motor 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.

  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 transmits a drive of the drive wheels 160 to the engine 120 and the motor generator 140, and an engine. Power split mechanism (for example, a planetary gear mechanism described later) 200 that distributes the power generated by 120 to two paths of drive wheel 160 and motor generator 140B (MG (1) 140B), and motor generator 140 for driving Traveling battery 220 for charging electric power, and inverter that performs current control while converting the direct current of traveling battery 220 and the alternating current of motor generator 140A (MG (2) 140A) and motor generator 140B (MG (1) 140B) 240 and charging / discharging of traveling battery 220 A battery control unit (hereinafter referred to as a battery ECU (Electronic Control Unit)) 260 that manages and controls a state (for example, SOC (State Of Charge)), an engine ECU 280 that controls the operating state of the engine 120, and a hybrid vehicle state. Accordingly, MG_ECU 300 that controls motor generator 140, battery ECU 260, inverter 240, and the like, and battery ECU 260, engine ECU 280, MG_ECU 300, etc. are mutually managed and controlled so that the hybrid vehicle can operate most efficiently. HV_ECU 320 and the like are included.

  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 (MG (2) 140A) or motor generator 140B (MG (1) 140B), so that motor generator 140A (MG (2) When power is supplied to 140A) or motor generator 140B (MG (1) 140B), the boost converter 242 boosts the power.

  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 are integrated as shown by a dotted line in FIG. 1). An example of this is the ECU.

  In power split mechanism 200, a planetary gear mechanism (planetary gear) is used to distribute the power of engine 120 to both drive wheel 160 and motor generator 140B (MG (1) 140B). By controlling the rotation speed of motor generator 140B (MG (1) 140B), power split device 200 also functions as a continuously variable transmission. The rotational force of the engine 120 is input to the carrier (C), which is output to the motor generator 140B (MG (1) 140B) by the sun gear (S), and the motor generator 140A (MG (2) 140A) and output by the ring gear (R). It is transmitted to the shaft (drive wheel 160 side). 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 (MG (1) 140B), and the rotational speed of the engine 120 is reduced. Let

  In a hybrid vehicle equipped with a hybrid system as shown in FIG. 1, if a predetermined condition is satisfied for the state of the vehicle, HV_ECU 320 uses only motor generator 140A (MG (2) 140A) of motor generator 140 to hybrid vehicle. The engine 120 is controlled via motor generator 140A (MG (2) 140A) and engine ECU 280 so as to perform the following traveling. For example, the predetermined condition is a condition that the SOC of traveling battery 220 is equal to or greater than a predetermined value. In this way, the hybrid vehicle can be driven only by the motor generator 140A (MG (2) 140A) when the engine 120 is inefficient at the time of starting or running at a low speed. As a result, the SOC of the traveling battery 220 can be reduced (the traveling battery 220 can be charged when the vehicle is subsequently stopped).

  Further, 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 motor generator 140B (MG (1) 140B) is driven to generate power. To do. At this time, motor generator 140A (MG (2) 140A) is driven by the generated electric power to assist driving of driving wheels 160. Further, at the time of high speed traveling, the electric power from the traveling battery 220 is further supplied to the motor generator 140A (MG (2) 140A) to increase the output of the motor generator 140A (MG (2) 140A) to the driving wheel 160. To add driving force. On the other hand, at the time of deceleration, motor generator 140 </ b> A (MG (2) 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 is reduced and charging is particularly necessary, the output of engine 120 is increased to increase the amount of power generated by motor generator 140B (MG (1) 140B), and traveling battery 220 is increased. Increase the amount of charge for.

  In addition, the target SOC of traveling battery 220 is normally set to about 60% so that energy can be recovered no matter when regeneration is performed. Further, the upper limit value and the lower limit value of the SOC are set, for example, with the upper limit value set to 80% and the lower limit value set to 30% in order to suppress the deterioration of the battery of the traveling battery 220. The HV_ECU 320 is set via the MG_ECU 300. Thus, power generation and regeneration by the motor generator 140 and motor output are controlled so that the SOC does not exceed the upper limit value and the lower limit value. In addition, the value quoted here is an example and is not a particularly limited value.

  The power split mechanism 200 will be further described with reference to FIG. The power split mechanism 200 includes a sun gear (S) 202 (hereinafter simply referred to as the sun gear 202), a pinion gear 204, a carrier (C) 206 (hereinafter simply referred to as the carrier 206), and a ring gear (R) 208 ( Hereinafter, it is composed of a planetary gear including a ring gear 208).

  Pinion gear 204 is engaged with sun gear 202 and ring gear 208. The carrier 206 supports the pinion gear 204 so that it can rotate. Sun gear 202 is coupled to the rotation shaft of MG (1) 140B. Carrier 206 is connected to the crankshaft of engine 120. Ring gear 208 is connected to the rotation shaft of MG (2) 140A and reduction gear 180.

  Engine 120, MG (1) 140B and MG (2) 140A are connected via power split mechanism 200 formed of a planetary gear, so that the rotational speeds of engine 120, MG (1) 140B and MG (2) 140A Are connected by a straight line in the nomograph.

  With reference to FIG. 3, engine 120 mounted on the hybrid vehicle will be described. The engine 120 is controlled by the engine ECU 280.

  As shown in FIG. 3, to engine 120, an intake system 1152 and an exhaust system 1154 including a first three-way catalytic converter 1200 and a second three-way catalytic converter 1300 are connected. Note that the number of three-way catalytic converters is not limited to two and may be one or more.

  Intake system 1152 includes an intake passage 1110, an air cleaner 1118, an air flow meter 1104, a throttle motor 1114A, a throttle valve 1112, and a throttle position sensor 1114B.

  Air taken in from air cleaner 1118 passes through intake passage 1110 and circulates to engine 120. A throttle valve 1112 is provided in the middle of the intake passage 1110. Throttle valve 1112 is opened and closed by throttle motor 1114 </ b> A that operates based on a control signal from engine ECU 280 so that a desired amount of air is supplied to engine 120. At this time, the opening degree of the throttle valve 1112 can be detected by the throttle position sensor 1114B. Throttle position sensor 1114B transmits the opening degree of throttle valve 1112 to engine ECU 280. An air flow meter 1104 is provided in the intake passage between the air cleaner 1118 and the throttle valve 1112 to detect the amount of intake air. Air flow meter 1104 transmits an intake air intake amount signal to engine ECU 280.

  Engine ECU 280 receives a vehicle speed signal from the vehicle speed sensor and a brake signal indicating that the driver is performing a brake operation from the brake switch.

  Engine 120 includes a cooling water passage 1122, a cylinder block 1124, an injector 1126, a piston 1128, a crankshaft 1130, a water temperature sensor 1106, and a crank position sensor 1132.

  Pistons 1128 are respectively provided in the number of cylinders corresponding to the number of cylinders of the cylinder block 1124. The mixture of the fuel injected from the injector 1126 and the intake air is introduced into the combustion chamber above the piston 1128 through the intake passage 1110, and burns by ignition of the ignition plug whose ignition timing is controlled. When combustion occurs, the piston 1128 is pushed down. At this time, the vertical motion of the piston 1128 is converted into a rotational motion of the crankshaft 1130 via the crank mechanism. The engine speed NE of the engine 120 is detected by the engine ECU 280 based on a signal detected by the crank position sensor 1132.

  A cooling water passage 1122 is provided in the cylinder block 1124, and the cooling water circulates by the operation of a water pump (not shown). The cooling water in the cooling water passage 1122 flows to a radiator (not shown) connected to the cooling water passage 1122 and is radiated by a cooling fan (not shown). A water temperature sensor 1106 is provided on the cooling water passage 1122 and detects the temperature of the cooling water in the cooling water passage 1122. Water temperature sensor 1106 transmits the detected water temperature to engine ECU 280 as a detection signal of engine cooling water temperature THW.

  Exhaust system 1154 is provided in exhaust passage 1108, first three-way catalytic converter 1200 that is integrated with, for example, the exhaust manifold of engine 120, for example, on the under floor, in order to increase the temperature of engine 120 due to heat. Second three-way catalytic converter 1300. An air-fuel ratio sensor is provided on the upstream side of the first three-way catalytic converter 1200 and on the upstream side of the second three-way catalytic converter 1300 (downstream side of the first three-way catalytic converter 1200). Furthermore, a temperature sensor that detects the temperatures of the first three-way catalytic converter 1200 and the second three-way catalytic converter 1300 may be provided.

  As described above, the exhaust passage 1108 connected to the exhaust side of the engine 120 is connected to the first three-way catalytic converter 1200 and the second three-way catalytic converter 1300. That is, the exhaust gas generated by the combustion of the air-fuel mixture in the combustion chamber in the engine 120 first flows into the first three-way catalytic converter 1200. HC and CO contained in the exhaust gas flowing into the first three-way catalytic converter 1200 are oxidized in the first three-way catalytic converter 1200. Further, NOx contained in the exhaust gas flowing into the first three-way catalytic converter 1200 is reduced in the first three-way catalytic converter 1200. The first three-way catalytic converter 1200 is installed near the engine 120 (may be integrated with the exhaust manifold as described above), and the temperature is quickly raised even when the engine 120 is cold started. To express the catalytic function.

  Further, the exhaust gas is sent from the first three-way catalytic converter 1200 to the second three-way catalytic converter 1300 for the purpose of purification. The first three-way catalytic converter 1200 and the second three-way catalytic converter 1300 basically have the same structure and function.

  First air-fuel ratio sensor 1210 provided upstream of first three-way catalytic converter 1200, provided downstream of first three-way catalytic converter 1200 and upstream of second three-way catalytic converter 1300 The second air-fuel ratio sensor 1310 thus detected detects the concentration of oxygen contained in the exhaust gas passing through the first three-way catalytic converter 1200 or the second three-way catalytic converter 1300. By detecting the oxygen concentration, it is possible to detect the so-called air-fuel ratio of the fuel and air contained in the exhaust gas.

  The first air-fuel ratio sensor 1210 and the second air-fuel ratio sensor 1310 generate a current corresponding to the oxygen concentration in the exhaust gas. This current is converted into a voltage, for example, and input to engine ECU 280. Accordingly, the air-fuel ratio of the exhaust gas upstream of the first three-way catalytic converter 1200 can be detected from the output signal of the first air-fuel ratio sensor 1210, and the second output signal from the second air-fuel ratio sensor 1310 can be detected. The air-fuel ratio of the exhaust gas upstream of the three-way catalytic converter 1300 can be detected. The first air-fuel ratio sensor 1210 and the second air-fuel ratio sensor 1310 generate, for example, a voltage of about 0.1 V when the air-fuel ratio is lean, and a voltage of about 0.9 V when the air-fuel ratio is rich. It is what happens. The value converted into the air-fuel ratio based on these values is compared with the air-fuel ratio threshold value, and air-fuel ratio control is performed by engine ECU 280.

  The first three-way catalytic converter 1200 and the second three-way catalytic converter 1300 function to reduce NOx while oxidizing HC and CO when the air-fuel ratio is substantially the stoichiometric air-fuel ratio, that is, HC, CO, and NOx. It has the function to purify simultaneously.

  In the present embodiment, ISC learning control in an internal combustion engine that is intermittently operated is executed without giving a shock to the driver and avoiding deterioration of fuel consumption. The ISC learning control is performed in a stable idle state (without changing the engine speed without changing the throttle opening). That is, learning control is performed only in the region of the extremely narrow throttle opening (throttle opening in the idle state). This is because if the throttle opening is changed in a stable idling state, the engine speed changes and ISC learning becomes difficult. Of course, it goes without saying that the ISC learning control cannot be executed when the engine 120 is stopped intermittently.

  Engine ECU 280, which is a control device according to the present embodiment, shocks the driver when ISC learning control is not executed and engine 120 is warmed up to the extent that ISC learning control is possible. The engine is operated without giving the ISC learning control.

  Such a control device according to the present embodiment is read out from the CPU (Central Processing Unit) and the memory included in the engine ECU 280 and executed by the CPU even in hardware mainly composed of digital circuits and analog circuits. It can also be realized by software mainly composed of programs to be executed. In general, it is said that it is advantageous in terms of operation speed when realized by hardware, and advantageous in terms of design change when realized by software. Below, the case where a control apparatus is implement | achieved as software is demonstrated.

  With reference to FIG. 4, a control structure of a program at the time of ISC learning control executed by engine ECU 280 which is the control apparatus according to the present embodiment will be described. This program is described as a subroutine program that is repeatedly executed at a predetermined cycle time.

  In step (hereinafter, step is referred to as S) 1000, engine ECU 280 determines whether or not ISC learning has not been executed. At this time, engine ECU 280 determines that ISC learning has not been executed unless the ISC learning completion flag stored in the memory in engine ECU 280 is set. If ISC learning has not been executed (YES in S1000), the process proceeds to S1010. If not (NO in S1000), the process proceeds to S1070.

  In S1010, engine ECU 280 detects engine coolant temperature THW. At this time, engine ECU 280 detects engine cooling water temperature THW based on the signal input from water temperature sensor 1106.

  In S1020, engine ECU 280 determines whether engine coolant temperature THW is equal to or higher than threshold value THW (1). For this threshold value THW (1), for example, the lowest engine cooling water temperature at which ISC learning control can be executed is set. If engine coolant temperature THW ≧ threshold value THW (1) (YES in S1020), the process proceeds to S1030. If not (NO in S1020), the process proceeds to S1070.

  In S1030, engine ECU 280 detects vehicle speed V of the hybrid vehicle. At this time, engine ECU 280 detects vehicle speed V based on a signal indicating engine speed NE detected by crank position sensor 1132. Further, the vehicle speed V may be detected based on a signal input from the vehicle speed sensor.

  In S1040, engine ECU 280 determines whether vehicle speed V is equal to or lower than threshold value V (1). For this threshold value V (1), for example, a low vehicle speed is set such that the vehicle will soon stop and ISC learning control will be executed. If vehicle speed V ≦ threshold value V (1) (YES in S1040), the process proceeds to S1050. If not (NO in S1040), the process proceeds to S1070.

  In S1050, engine ECU 280 determines whether or not the driver is operating a brake. At this time, engine ECU 280 determines whether or not the driver is operating a brake based on the brake signal input from the brake switch. If the driver is operating the brake (YES in S1050), the process proceeds to S1060. If not (NO in S1060), the process proceeds to S1070.

  In S1060, engine ECU 280 sets an engine stop prohibition flag and maintains engine 120 in an operating state. For example, even if an engine stop command signal is received from HV_ECU 320, engine 120 is not stopped. Note that the processing of S1060 in the state where the engine stop prohibition flag is set maintains the state where the engine stop prohibition flag is set. Thereafter, the process proceeds to S1080.

  In S1070, engine ECU 280 resets the engine stop prohibition flag and permits engine 120 to stop. For example, when an engine stop command signal is received from HV_ECU 320, engine 120 is stopped. Note that the processing of S1070 in the state where the engine stop prohibition flag is reset maintains the state where the engine stop prohibition flag is reset. Thereafter, this process ends.

  In S1080, engine ECU 280 determines whether or not an ISC learning condition is satisfied. At this time, for example, when the hybrid vehicle is stopped and the idle state is stabilized (no transient state and no response delay), engine ECU 280 determines that the condition for starting ISC learning (ISC learning condition) is satisfied. To do. If the ISC learning condition is satisfied (YES in S1080), the process proceeds to S1090. If not (NO in S1080), the process returns to S1080. If NO in S1080, this subroutine process may be terminated.

  In S1090, engine ECU 280 executes ISC learning control. Thereafter, this process ends. When ISC learning control is completed, engine ECU 280 sets an ISC learning completion flag stored in the memory. In addition, engine ECU 280 resets the engine stop prohibition flag and permits intermittent operation of engine 120.

  FIG. 5 is a timing chart when the control of the present invention is executed for the ISC learning control operation of the engine 120 controlled by the control device (ECU) according to the present embodiment based on the above-described structure and flowchart. A description will be given with reference to FIG. 6 which is a timing chart when the conventional control for comparison with FIG. 5 is executed. In the following description of the operation, only the case where ISC learning is not executed will be described.

  During operation of this hybrid vehicle, engine 120 is warmed up by operation of engine 120, and engine coolant temperature THW becomes equal to or higher than threshold value THW (1) (YES in S1020). This timing is time T (1) in FIGS. At this time, it is assumed that the engine stop prohibition flag is in the reset state and the engine stop is permitted, and the engine 120 is stopped.

  When the driver operates the brake at time T (2) (depresses the brake pedal), vehicle speed V becomes equal to or lower than threshold value V (1) (YES in S1040). This timing is time T (3) in FIG. It is assumed that the driver is operating the brake continuously from time T (2) in FIG.

  Since the driver is operating the brake, it is determined that the brake is also ON at time T (3) in FIG. 5 (YES in S1050), and the engine stop prohibition flag is set. Therefore, at time T (3) in FIG. 5, engine 120 that has been stopped is started. At this time, since the driver is stepping on the brake pedal and the hybrid vehicle is traveling, the start shock of the engine 120 is reduced.

  If the ISC learning condition is satisfied (YES in S1080) by stopping the hybrid vehicle or the like, ISC learning is executed. The ISC learning condition is satisfied at time T (4) in FIG. 5, and the ISC learning is executed until time T (5).

  As a result, when controlled by engine ECU 280, which is the control device according to the present embodiment, engine 120 is started during the driver's braking operation while the vehicle is running, so that the start shock of engine 120 is reduced. Can be reduced. Furthermore, as shown in FIG. 5, the time from the engine stop prohibition (operation request of the engine 120) to the completion of ISC learning can be shortened.

  On the other hand, in the prior art, as shown in FIG. 6, in order to avoid engine start when the brake is not operated (in order to avoid that the driver is likely to feel an engine start shock), warm-up is completed and engine operation is not performed. The engine stop prohibition flag was set only under conditions (without considering vehicle speed V and brake operation). The engine stop prohibition flag is set from time T (1) in FIG. 6 and the engine 120 is operating, or the engine stop prohibition flag is set and the engine 120 is operating from before time T (1). Therefore, as shown in FIG. 6, even if the engine 120 that has been stopped when the brake is not operated can be avoided, the time from the engine stop prohibition (operation request for the engine 120) to the completion of ISC learning is reduced. become longer. In other words, the time during which engine 120 cannot be stopped is lengthened, and fuel efficiency is deteriorated.

  As described above, the control device according to the present embodiment consumes fuel wastefully while reducing ISC learning control of the engine mounted on the hybrid vehicle, which is felt by the engine starting. In such a manner, the ISC learning control can be executed.

  In the above-described embodiment, the ISC learning control has been described. However, the application of the present invention is not limited to this. For example, the present invention can also be applied to learning control of air-fuel ratio feedback control using an air-fuel ratio sensor. It is.

  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 control block diagram of an entire hybrid vehicle including a control device according to an embodiment of the present invention. It is a figure which shows a power split mechanism. It is a control block diagram of an engine which is a control target of an engine ECU which is a control device according to an embodiment of the present invention. It is a flowchart which shows the control structure of the program performed by engine ECU which is a control apparatus which concerns on embodiment of this invention. 5 is a timing chart showing temporal changes in the state of the engine when the flowchart shown in FIG. 4 is executed. 6 is a timing chart showing temporal changes in the state of the engine when conventional control compared with the timing chart shown in FIG. 5 is executed.

Explanation of symbols

  120 Engine, 140 Motor Generator, 160 Drive Wheel, 180 Reducer, 200 Power Dividing Mechanism, 220 Travel Battery, 240 Inverter, 242 Boost Converter, 260 Battery ECU, 280 Engine ECU, 300 MG_ECU, 320 HV_ECU, 1104 Air Flow Meter 1106 Water temperature sensor, 1108 exhaust passage, 1110 intake passage, 1112 throttle valve, 1114A throttle motor, 1114B throttle position sensor, 1118 air cleaner, 1122 cooling water passage, 1124 cylinder block, 1126 injector, 1128 piston, 1130 crankshaft, 1132 crank Position sensor, 1152 Intake system, 1154 Exhaust system, 1200 First three One-way catalytic converter, 1300 Second three-way catalytic converter.

Claims (3)

A control device for a hybrid vehicle having an internal combustion engine and a power source other than the internal combustion engine as a travel source of the vehicle,
Control means for controlling the internal combustion engine to temporarily stop the internal combustion engine when the vehicle condition satisfies a temporary stop condition and restart the internal combustion engine when the restart condition is satisfied;
In the operating region where the internal combustion engine is operating stably, learning execution means for executing control amount learning;
Means for detecting the operating state of the braking device operated by the driver;
Detecting means for detecting the speed of the vehicle;
Prohibiting means for prohibiting temporary stop of the internal combustion engine when the vehicle is capable of learning and satisfies the condition that the braking device operates and the speed is equal to or lower than a predetermined speed. And a control device.   The prohibiting means is a state of the vehicle in which the internal combustion engine is warmed up and can be learned, and when the braking device is operated and the speed is equal to or lower than a predetermined speed, The control device according to claim 1, comprising means for prohibiting a temporary stop of the engine.   3. The control device according to claim 1, wherein the learning execution unit includes a unit for performing learning of an air flow rate for maintaining an idle speed of the internal combustion engine.

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