JP2009079549A - Cooling control device for recirculation gas recirculated from exhaust pipe to intake pipe of internal combustion engine, control method, program for realizing the method, and recording medium recording the program - Google Patents

Abstract

In a vehicle using an internal combustion engine that recirculates exhaust gas and a rotating electrical machine as a power source, the temperature increase of the recirculation gas when the recirculation valve is abnormal is accurately suppressed, and deterioration due to overheating of peripheral components of an intake pipe is suppressed. To do.
An ECU controls a water pump so as to maximize the flow rate of engine cooling water flowing through an EGR cooler when an opening abnormality occurs in an EGR valve. The ECU determines the required engine power in advance when the flow rate of cooling water from the water pump is maximized (YES in S202) and the engine water temperature exceeds the threshold value α (YES in S204). The target engine speed is calculated based on the engine required power (S208), and the speed of MG (1) is controlled so as to be the target engine speed (S210). ).
[Selection] Figure 8

Description

  The present invention relates to cooling control of recirculation gas that is recirculated from an exhaust pipe of an internal combustion engine to an intake pipe, and more particularly to a technique for cooling the recirculation gas using cooling water of the internal combustion engine.

  An exhaust gas recirculation device (hereinafter also referred to as an EGR (Exhaust Gas Recirculation) device) provided in a vehicle engine or the like recirculates a part of the exhaust gas to the intake side of the engine, and thereby contains NOx contained in the exhaust gas. Reduce. In the EGR device, the flow rate of the recirculated gas is adjusted by controlling the recirculation valve provided in the recirculation passage communicating the exhaust pipe and the intake pipe of the engine according to the operating state of the engine. When an open failure occurs in which the recirculation valve opens more than the target value, a larger amount of exhaust gas circulates than when it is normal. As a result, the combustion state of the engine may deteriorate, or the peripheral components of the intake pipe including the recirculation valve may be overheated by the high-temperature exhaust gas and deteriorate. Techniques for solving such problems are disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-76551 (Patent Document 1) and Japanese Patent Application Laid-Open No. 9-25852 (Patent Document 2).

  The control device disclosed in Patent Document 1 discloses a technique for suppressing deterioration of the combustion state of the engine when the recirculation valve is open. The control device disclosed in Patent Document 1 is provided in a throttle valve, a pipe line that communicates the exhaust system and the intake system with each other, and a part of the pipe line, and exhaust gas of an amount corresponding to the opening degree is provided in the exhaust system. The vehicle is controlled with an internal combustion engine having at least one of a power source and an exhaust gas circulation device having a circulation amount control valve that can be circulated from the engine to the intake system. The control device includes: a determination unit for determining whether or not the circulation amount control valve is in an open fixing state defined as a state in which the circulation amount control valve is fixed in a state having an opening greater than or equal to a predetermined value; When it is determined that the required torque specifying means for specifying the required torque and the circulation amount control valve are in the open fixed state, and the required torque is equal to or greater than a threshold value, the throttle valve has a predetermined value including the fully opened opening degree. Control means for operating the internal combustion engine with the above opening degree and stopping the internal combustion engine when the required torque is less than the threshold value is included.

  According to the control device disclosed in Patent Document 1, the required torque for the internal combustion engine is specified by the required torque specifying means. In the case where the circulation amount control valve is in the open fixed state, if the required torque is equal to or greater than the threshold value, the internal combustion engine is operated in a state where the throttle valve has an opening greater than or equal to a predetermined value including the fully opened opening. As a result, the internal combustion engine is operated in a state where the throttle valve is limited to an opening range in which the combustion state can be satisfactorily maintained, so that deterioration of the combustion state can be prevented. On the other hand, if the required torque is less than the threshold value, the internal combustion engine is stopped, so that deterioration of the combustion state can be inevitably prevented.

  The engine fail-safe device disclosed in Patent Document 2 discloses a technique for preventing a secondary failure due to overheating when the reflux valve is open. The fail-safe device disclosed in Patent Document 2 is an engine including an exhaust gas recirculation passage that connects an exhaust passage and an intake air passage, and an exhaust gas recirculation control valve that opens and closes the exhaust gas recirculation passage according to an operating state. Means for diagnosing an open failure that opens larger than the target value and means for stopping fuel injection to the engine when the engine speed exceeds a predetermined value at the time of the open failure are included.

According to the fail-safe device disclosed in Patent Document 2, when the engine speed exceeds a predetermined value during an open failure in which the exhaust gas recirculation control valve remains open and the exhaust gas recirculation amount becomes excessive, fuel injection into the engine is performed. By stopping the operation, the engine is prevented from being operated to generate a high output. Thereby, it is possible to prevent the exhaust gas recirculation control valve from being overheated by the high-temperature exhaust gas to cause a secondary failure or to deteriorate the performance of the engine body.
JP 2007-76551 A Japanese Patent Laid-Open No. 9-25852

  By the way, in the control device disclosed in Patent Document 1, even when the circulation amount control valve is in the open fixing state, the operation of the internal combustion engine is continued if the required torque is equal to or greater than the threshold value. In the fail-safe device disclosed in Patent Document 2, even when the exhaust gas recirculation control valve is in an open failure, the operation of the internal combustion engine is continued when the engine speed is equal to or less than a predetermined value. As described above, if the operation of the internal combustion engine is continued, the increase in the temperature of the recirculation gas cannot be suppressed even though the recirculation valve opens more than the target value, and the vicinity of the intake pipe including the recirculation valve The case where parts deteriorate due to overheating is considered.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a recirculation gas when a recirculation valve is abnormal in a vehicle using an internal combustion engine that recirculates exhaust gas and a rotating electrical machine as power sources. Control apparatus, control method, program for realizing the method, and recording medium recording the program, which can appropriately suppress the temperature rise of the intake pipe and suppress deterioration due to overheating of the peripheral components of the intake pipe including the reflux valve Is to provide.

  A cooling control device according to a first aspect of the present invention is provided in a vehicle that uses an internal combustion engine and a rotating electrical machine connected to the internal combustion engine as a power source, and communicates an exhaust pipe of the internal combustion engine and an intake pipe of the internal combustion engine. Is used to control the cooling of the recirculated gas that is recirculated from the exhaust pipe to the intake pipe. The vehicle is provided with a recirculation valve that adjusts the flow rate of the recirculation gas, a cooling water pipe through which the cooling water of the internal combustion engine circulates, a part of which contacts the recirculation passage, and a pump mechanism that adjusts the flow rate of the cooling water. . The cooling control device includes a means for calculating the required power of the internal combustion engine based on the state of the vehicle, a means for determining whether or not the recirculation valve is in an abnormal state that opens larger than the target value, When the condition is satisfied, the pump control means for controlling the pump mechanism and the predetermined condition regarding the temperature of the recirculation gas are satisfied so that the flow rate of the cooling water is increased compared to the case where the condition is not abnormal. Compared to a case where the required power is not satisfied, and at least one of the internal combustion engine and the rotating electrical machine so as to reduce the amount of heat generated in the internal combustion engine when the required power is reduced by the reduction means And control means for controlling. The control method according to the fifth invention has the same requirements as the control device according to the first invention.

  According to the first or fifth aspect of the invention, when the reflux valve is in an abnormal state that opens larger than the target value, the pump mechanism is controlled to increase the flow rate of the cooling water flowing through the cooling water piping that contacts the reflux passage. . Thereby, the cooling efficiency of the reflux gas in the reflux passage can be improved while continuing the operation of the internal combustion engine. Further, when a predetermined condition relating to the temperature of the recirculation gas is satisfied, the required power of the internal combustion engine is reduced, and the internal combustion engine and the engine are rotated so as to reduce the amount of heat generated in the internal combustion engine based on the reduced required power. At least one of electricity is controlled. In this way, for example, when the temperature of the recirculation gas rises to a temperature at which it is assumed that the temperature of the peripheral components of the intake pipe including the recirculation valve exceeds the allowable temperature, the amount of heat generated in the internal combustion engine is reduced, The temperature can be lowered. As a result, when the recirculation valve is abnormal, an increase in the temperature of the recirculation gas can be appropriately suppressed, and deterioration due to overheating of peripheral components around the intake pipe including the recirculation valve can be suppressed. As a result, in a vehicle that uses an internal combustion engine that recirculates exhaust gas and a rotating electrical machine as a power source, the temperature rise of the recirculation gas when the recirculation valve is abnormal is appropriately suppressed, and the peripheral components of the intake pipe including the recirculation valve are reduced. It is possible to provide a cooling control device and a control method capable of suppressing deterioration due to overheating.

  In the cooling control apparatus according to the second aspect of the invention, in addition to the configuration of the first aspect, the predetermined condition is that the temperature of the cooling water is set in advance when the flow rate of the cooling water is increased by the pump control means. It is a condition that the temperature is higher than a predetermined temperature. The control method according to the sixth invention has the same requirements as the control device according to the second invention.

  According to the 2nd or 6th invention, when the temperature of cooling water is high, it is estimated that the cooling efficiency of reflux gas falls and the temperature of reflux gas is high. Therefore, when the flow rate of the cooling water is increased by the pump control means, the required power of the internal combustion engine is reduced when the temperature of the cooling water is higher than a predetermined temperature. In this way, if the cooling water temperature is low and the reflux gas cooling efficiency is good when the reflux valve is abnormal, the temperature of the reflux gas is increased only by increasing the flow rate of the cooling water without reducing the required power. Can be suppressed. Therefore, deterioration due to overheating of the peripheral components of the intake pipe can be suppressed without reducing the running power of the vehicle.

  In the cooling control apparatus according to the third invention, in addition to the configuration of the first or second invention, the vehicle includes an internal combustion engine, a rotating electrical machine, and a power distribution mechanism connected to a drive shaft of the vehicle. The control means includes means for controlling the rotating electrical machine so as to reduce the rotational speed of the internal combustion engine via the distribution mechanism when the required power is reduced by the reduction means. The control method according to the seventh invention has the same requirements as the control device according to the third invention.

  According to the third or seventh invention, when the required power is reduced, the amount of heat generated in the internal combustion engine is reduced by controlling the rotating electrical machine and reducing the rotational speed of the internal combustion engine via the distribution mechanism, An increase in the temperature of the reflux gas can be suppressed.

  In the cooling control apparatus according to the fourth aspect of the invention, in addition to the configuration of the first or second aspect of the invention, a throttle valve for adjusting the amount of air taken into the internal combustion engine is provided in the intake pipe. The operation control means includes means for controlling the throttle valve so as to reduce the air amount when the required power is reduced by the reduction means. The control method according to the eighth invention has the same requirements as the control device according to the fourth invention.

  According to the fourth or eighth invention, when the required power is reduced, the amount of heat generated in the internal combustion engine is reduced by controlling the throttle valve to reduce the amount of air sucked into the internal combustion engine, thereby Temperature rise can be suppressed.

  In the program according to the ninth invention, a computer is caused to execute the control method according to any of the fifth to eighth inventions. A recording medium according to a tenth invention is a medium in which a program for causing a computer to execute the control method according to any of the fifth to eighth inventions is recorded in a computer-readable manner.

  According to the ninth or tenth invention, the control method according to any of the fifth to eighth 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.

  A hybrid vehicle 10 equipped with a control device according to the present embodiment will be described with reference to FIG. The vehicle to which the present invention can be applied is not limited to the hybrid vehicle 10 shown in FIG. 1, and may be a hybrid vehicle having another aspect.

  Hybrid vehicle 10 includes an engine 100 and motor generators 300A, 300B (MG (1) 300A, MG (2) 300B). In the following, for convenience of explanation, MG (1) 300A and MG (2) 300B are also referred to as motor generator 300 when they are described without being distinguished. Regenerative braking is performed when motor generator 300 functions as a generator. When motor generator 300 functions as a generator, the kinetic energy of the vehicle is converted into electric energy, a regenerative braking force (regenerative brake) is generated, and the vehicle is decelerated.

  In addition to this, the hybrid vehicle 10 includes a speed reducer 14 that transmits power generated by the engine 100 and the motor generator 300 to the drive wheels 12, and transmits driving of the drive wheels 12 to the engine 100 and the motor generator 300. , Power split mechanism 200 that distributes the power generated by engine 100 to output shaft 212 and MG (1) 300A, travel battery 310 that charges power for driving motor generator 300, and travel battery 310 Inverter 330 that performs current control while converting direct current and alternating current of motor generator 300, engine ECU 406 that controls the operating state of engine 100, motor generator 300, inverter 330, and battery for traveling according to the state of hybrid vehicle 10 Control charge / discharge status of 310 To include a MG_ECU402, and mutually managing and controlling engine ECU406 and MG_ECU402 like, the HV_ECU404 for controlling the entire hybrid system such hybrid vehicle 10 can travel most efficiently.

  A boost converter 320 is provided between the traveling battery 310 and the inverter 330. Since the rated voltage of traveling battery 310 is lower than the rated voltage of motor generator 300, when power is supplied from traveling battery 310 to motor generator 300, boost converter 320 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, as shown by a dotted line in FIG. 1, an example is an ECU 400 in which MG_ECU 402 and HV_ECU 404 are integrated. In the following description, MG_ECU 402 and HV_ECU 404 are described as ECU 400 without distinction.

  The ECU 400 includes an engine ECU 406, a vehicle speed sensor, an accelerator opening sensor, a brake stroke sensor, a throttle opening sensor, an MG (1) rotation speed sensor, an MG (2) rotation speed sensor, an engine rotation speed sensor, an air flow meter (all (Not shown) and a signal from the monitoring unit 340 are input.

  The vehicle speed sensor detects the vehicle speed V from the rotation speed of the drive shaft 16 and transmits a signal representing the detection result to the ECU 400.

  The accelerator opening sensor detects an accelerator pedal opening (accelerator opening) ACC, and transmits a signal representing the detection result to ECU 400.

  The brake stroke sensor detects a brake pedal stroke (brake stroke) BS and transmits a signal representing the detection result to ECU 400.

  The throttle opening sensor detects the opening (throttle opening) of a throttle valve (not shown) used for adjusting the amount of air (absorbed air) KL sucked into engine 100, and outputs a signal representing the detection result. It transmits to ECU400.

  MG (1) rotation speed sensor detects rotation speed NM (1) of MG (1) 300A, and transmits a signal representing the detection result to ECU 400.

  The MG (2) rotational speed sensor detects the rotational speed NM (2) of MG (2) 300B and transmits a signal representing the detection result to ECU 400.

  The engine speed sensor is connected to engine ECU 406, detects the rotational speed (engine speed) NE of crankshaft 102, which is the output shaft of engine 100, and transmits a signal representing the detection result to ECU 400 via engine ECU 406. To do.

  The air flow meter is connected to the engine ECU 406, detects an intake air amount KL introduced into the combustion chamber of the engine 100 via an intake pipe from an air cleaner (not shown), and sends a signal representing the detection result to the engine ECU 406. To ECU 400.

  The monitoring unit 340 is connected to the traveling battery 310 and monitors the state of the traveling battery 310. The monitoring unit 340 includes a voltage sensor, a current sensor, and a temperature sensor (all not shown) provided in the traveling battery 310, a voltage value between terminals of the traveling battery 310, and a charge / discharge current value of the traveling battery 310. Information such as (battery current value) I and temperature (battery temperature) TB of the traveling battery 310 is input. The monitoring unit 340 calculates the remaining capacity of the traveling battery 310 based on information such as the battery current value I and the battery temperature TB.

  The ECU 400 includes an engine ECU 406, a vehicle speed sensor, an accelerator opening sensor, a brake stroke sensor, a throttle opening sensor, an MG (1) rotation speed sensor, an MG (2) rotation speed sensor, a monitoring unit 340, an engine rotation speed sensor, and an air flow. Based on a signal sent from a meter or the like, a map stored in a ROM (Read Only Memory), and a program, the devices are controlled so that the vehicle is in a desired running state.

  The power split mechanism 200 will be further described with reference to FIGS. 2 and 3. Power split device 200 includes a planetary gear including a sun gear 202, a pinion gear 204, a carrier 206, and 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) 300A. Carrier 206 is coupled to crankshaft 102 of engine 100. Ring gear 208 is coupled to output shaft 212.

  Engine 100, MG (1) 300A and MG (2) 300B are coupled via power split mechanism 200 made of planetary gears, so that rotation of engine 100, MG (1) 300A and MG (2) 300B is performed. For example, as shown in FIG. 3, the numbers are related by a straight line in the nomograph (FIG. 3 is an example during steady operation).

  Engine 100 according to the present embodiment will be described with reference to FIGS. 4 and 5. Engine 100 includes an intake pipe 110, an exhaust pipe 120, and an EGR pipe 130.

  In engine 100, air drawn from an air cleaner (not shown) flows through intake pipe 110 and is introduced into the combustion chamber of engine 100. The intake air amount KL is adjusted by the opening degree of the throttle valve 114. The opening degree of throttle valve 114 is controlled by throttle motor 112 that operates based on a signal from engine ECU 406. The exhaust gas after combustion of the air-fuel mixture passes through a three-way catalytic converter 122 provided in the middle of the exhaust pipe 120 and is discharged to the atmosphere.

  Further, the engine 100 is provided with a vacuum sensor 118 and an engine water temperature sensor 124. Vacuum sensor 118 detects the pressure in intake pipe 110 downstream of throttle valve 114 and transmits a signal representing the detection result to engine ECU 406. Engine water temperature sensor 124 detects the temperature of the coolant flowing through the water jacket formed in engine 100 (engine water temperature), and transmits a signal representing the detection result to engine ECU 406. It should be noted that signals representing detection detection results of vacuum sensor 118 and engine water temperature sensor 124 are also transmitted to ECU 400 via engine ECU 406.

  The engine 100 recirculates a part of the exhaust gas in the exhaust pipe 120 to the intake pipe 110 via the EGR pipe 130 and mixes it with new air-fuel mixture to lower the combustion temperature, thereby generating nitrogen oxides (NOx). In order to improve fuel efficiency, it is possible to reduce fuel consumption and pumping loss. The EGR pipe 130 communicates the downstream side of the three-way catalytic converter 122 in the exhaust pipe 120 and the downstream side of the throttle valve 114 in the intake pipe 110. The exhaust gas after passing through the three-way catalytic converter 122 circulates through the EGR pipe 130 toward the intake pipe 110 as a recirculation gas.

  The EGR valve 132 is provided in the middle of the EGR pipe 130. Engine ECU 406 is controlled by an open command or a close command from engine ECU 406 or ECU 400. Thereby, the opening degree of the EGR valve 132 is controlled, and the flow rate of the reflux gas in the EGR pipe 130 is adjusted.

  In the middle of the EGR pipe 130, an EGR cooler 134 that cools the high-temperature reflux gas flowing through the EGR pipe 130 is provided. The inside of the EGR cooler 134 has a double pipe structure in which a cooling water passage for the engine 100 is provided outside the EGR pipe 130. By cooling the reflux gas with the EGR cooler 134, deterioration due to overheating of the EGR valve 132 and the intake pipe 110 is suppressed.

  FIG. 5 shows the structure of the cooling circuit of engine 100. As shown in FIG. 5, the cooling circuit of the engine 100 includes a radiator 140, a water jacket (not shown) formed in the engine 100, and cooling water passages 142 and 144 that connect the radiator 140 and the engine 100. And a bypass passage 152 communicating with the cooling water passages 142 and 144, a thermostat 150 for switching the cooling water flow path, a thermostat 150 for switching the cooling water flow path, and a connection between the cooling water passage 144 and the bypass passage 152. It is comprised from the water pump (W / P) 160 provided in between.

  The thermostat 150 is a switching valve that operates mechanically according to the temperature of the cooling water flowing through the thermostat 150. When the temperature of the cooling water is low, the thermostat 150 switches an internal valve so that the cooling water flows from the bypass passage 152 to the engine 100 side of the cooling water passage 144. When the temperature of the cooling water is high, the thermostat 150 switches an internal valve so as to block the flow of the cooling water from the bypass passage 152 to the cooling water passage 144. At this time, the cooling water flows into the cooling water passage 144 via the radiator 140.

  A cooling water passage 146 that connects the cooling water passages 142 and 144 in parallel with the bypass passage 152 is provided for the cooling circuit of the engine 100 having such a configuration. One end of cooling water passage 146 is connected to cooling water passage 142 between the connection position of bypass passage 152 and cooling water passage 142 and engine 100. The other end of the cooling water passage 146 is connected to the cooling water passage 144 between the water pump 160 and the thermostat 150. The EGR cooler 134 is provided in the middle of the cooling water passage 146.

  Water pump 160 adjusts the flow rate of cooling water circulating in the cooling circuit of engine 100. Water pump 160 is controlled by a control signal from engine ECU 406 or ECU 400. By the operation of the water pump 160, the cooling water is circulated as shown by the solid line arrow in FIG. 5 and circulates inside the EGR cooler 134. That is, the EGR cooler 134 cools the reflux gas using the cooling water flowing from the engine 100.

  In the present embodiment, when an abnormality that causes the EGR valve 132 to open larger than the target value (hereinafter also simply referred to as an opening abnormality) occurs, the high-temperature exhaust gas is recirculated in a larger amount than normal, There is a risk that intake system components such as the EGR pipe 130, the EGR valve 132, and the intake pipe 110 will be excessively heated and deteriorated.

  Therefore, in the cooling control apparatus according to the present embodiment, when the EGR valve 132 is abnormally open, the flow rate of the cooling water circulating through the cooling circuit of the engine 100 is increased, and the amount of heat generated in the engine 100 is reduced. Reduce the temperature of the reflux gas.

  With reference to FIG. 6, a functional block diagram of the cooling control apparatus according to the present embodiment will be described. As shown in FIG. 6, the cooling control device includes an abnormality detection unit 410, a flow rate calculation unit 420, a W / P control unit 430, an engine required power calculation unit 440, a target engine speed calculation unit 450, MG (1) control unit 460.

  The abnormality detection unit 410 detects an open abnormality in the EGR valve 132 based on the vacuum pressure from the vacuum sensor 118, for example.

  The flow rate calculation unit 420 calculates a required flow rate A of cooling water to be circulated in the cooling circuit of the engine 100 based on the engine speed NE, the engine water temperature, and the detection result of the abnormality detection unit 410. The W / P control unit 430 transmits a control signal corresponding to the required flow rate A to the water pump 160.

  The engine required power calculation unit 440 calculates the engine required power based on the accelerator opening ACC, the vehicle speed V, and the engine water temperature. The target engine speed calculation unit 450 calculates the target engine speed based on the required engine power.

  The MG (1) control unit 460 generates an engine based on the rotational speed MN (1) of the MG (1) 300A, the rotational speed MN (2) of the MG (2) 300B, the engine rotational speed NE, and the target engine rotational speed. The rotational speed of the MG (1) 300A is controlled so that the rotational speed NE becomes the target engine rotational speed.

  The control device according to the present embodiment having such a functional block is read out from a CPU (Central Processing Unit) and a memory and a memory included in the ECU even in hardware mainly composed of a digital circuit or an analog circuit. It can also be realized by software mainly composed of programs executed by the CPU. 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. Note that a recording medium on which such a program is recorded is also an embodiment of the present invention.

  With reference to FIG. 7, a control structure of a program executed by ECU 400 constituting the cooling control apparatus according to the present embodiment will be described. Note that this program is repeatedly executed at a predetermined cycle time.

  In step (hereinafter step is abbreviated as S) 100, ECU 400 calculates a required flow rate A of cooling water to be circulated in the cooling circuit of engine 100. For example, the ECU 400 calculates the required flow rate A based on the engine speed NE from the engine speed sensor and the engine water temperature from the engine water temperature sensor 124.

  In S102, ECU 400 determines whether an open abnormality has occurred in EGR valve 132 or not. For example, ECU 400 transmits an open command to EGR valve 132 after deceleration of hybrid vehicle 10 and then transmits a close command, and when the vacuum pressure from vacuum sensor 118 at that time does not change, an open abnormality has occurred. to decide. Note that the method of determining whether or not an open abnormality has occurred in the EGR valve 132 is not limited to this. If it is determined that an opening abnormality has occurred (YES in S102), the process proceeds to S104. Otherwise (NO in S102), the process proceeds to S106.

  In S104, ECU 400 changes requested flow rate A to the maximum value. If the required flow rate A is increased, it is not necessarily limited to changing the required flow rate A to the maximum value. In S106, ECU 400 transmits a control signal corresponding to required flow rate A to water pump 160.

  With reference to FIG. 8, a control structure of a program executed when ECU 400 configuring the cooling control apparatus according to the present embodiment controls the rotation speed of MG (1) 300A will be described. Note that this program is repeatedly executed at a predetermined cycle time.

  In S200, ECU 400 calculates engine required power. For example, the ECU 400 calculates the required power of the hybrid vehicle 10 and the engine load ratio at which the hybrid vehicle 10 can operate most efficiently based on the accelerator opening ACC and the vehicle speed V, and the required power and engine load ratio of the hybrid vehicle 10 are calculated. Is calculated as the required engine power. In addition, the calculation method of engine required power is not limited to this.

  In S202, ECU 400 determines whether or not the flow rate of water pump 160 is set to the maximum value. For example, ECU 400 determines that the flow rate of water pump 160 is set to the maximum value when the process of S104 in FIG. 7 is continued. If it is set to the maximum value (YES in S202), the process proceeds to S204. Otherwise (NO in S202), the process proceeds to S208.

  In S204, ECU 400 determines whether or not the engine water temperature has exceeded a predetermined threshold value α. The threshold value α is the engine water temperature corresponding to the temperature of the recirculated gas that is predicted to deteriorate the components of the intake system. The threshold value α is not limited to this value. If it is determined that threshold value α has been exceeded (YES in S204), the process proceeds to S206. Otherwise (NO in S204), the process proceeds to S208.

  In S206, ECU 400 limits engine required power to a predetermined upper limit value. Note that as long as the engine required power is reduced, the engine required power is not necessarily limited to a predetermined upper limit value.

  In S208, ECU 400 calculates a target engine speed based on the engine required power.

  In S210, ECU 400 controls the rotational speed of MG (1) 300A so as to be the target engine rotational speed. For example, the ECU 400 detects the rotational speed MN (1) of the MG (1) 300A and the rotational speed MN (2) of the MG (2) 300B, and displays the engine rotational speed on the alignment chart shown in FIG. The rotational speed of MG (1) 300A is controlled so that NE becomes the target engine rotational speed.

  The temperature of the reflux gas controlled by ECU 400 that constitutes the cooling control apparatus according to the present embodiment based on the above-described structure and flowchart will be described.

  As shown in FIG. 9, when an open abnormality occurs in EGR valve 132 at time T (1) (YES in S102), the flow rate of water pump 160 is maximized (S104, S106). Thereby, the cooling capacity of the EGR cooler 134 is improved, and the increase in the reflux gas temperature is suppressed as compared with the case where the flow rate is not set to the maximum value (see the one-dot chain line in FIG. 9).

  Until the time T (2) when the engine water temperature reaches the threshold value α, it is determined that the cooling efficiency of the recirculated gas is good and the temperature of the recirculated gas is equal to or lower than the temperature that is expected to deteriorate the components of the intake system. Thus, the temperature rise of the reflux gas is suppressed only by setting the flow rate of the cooling water to the maximum value. Therefore, deterioration due to overheating of the peripheral components of the intake pipe can be suppressed without reducing the traveling power of the hybrid vehicle 10.

  Thereafter, when the engine water temperature gradually rises and the engine water temperature exceeds threshold value α at time T (2) (YES in S204), the engine required power is limited (S206), and the engine required power is limited. Accordingly, the target engine speed is reduced (S208), and MG (1) 300A is controlled so as to be the reduced target engine speed (S210). As a result, the engine speed decreases, so the amount of heat generated by the engine 100, that is, the temperature of the exhaust gas decreases. Therefore, the increase in the reflux gas temperature is further suppressed as compared with the case where the engine required power is not limited (see the two-dot chain line in FIG. 9).

  As described above, according to the cooling control apparatus according to the present embodiment, when the EGR valve is abnormally open, the flow rate of the cooling water circulating in the engine cooling circuit is maximized and the flow rate of the cooling water is set. If the temperature of the cooling water exceeds the threshold value and the temperature of the reflux gas is estimated to be high, the temperature of the reflux gas is lowered by reducing the engine speed. As a result, when the EGR valve is abnormally opened, the temperature increase of the reflux gas can be appropriately suppressed, and deterioration due to overheating of the peripheral components of the intake pipe can be suppressed.

  In the present embodiment, the required engine power is limited when the flow rate of the cooling water is maximized and the engine water temperature exceeds the threshold value α. On the other hand, the engine required power may be limited when the engine water temperature exceeds the threshold value α regardless of whether or not the flow rate of the cooling water is set to the maximum value. That is, you may make it abbreviate | omit the process of S202 of the flowchart shown in FIG.

  In this embodiment, a temperature sensor for the recirculation gas is provided, and the engine required power is limited when the temperature of the recirculation gas detected by the temperature sensor reaches a temperature that is predicted to deteriorate the components of the intake system. You may make it do. That is, in the process of S204 in the flowchart shown in FIG. 8, it may be determined whether or not the temperature of the recirculated gas detected by the temperature sensor exceeds a temperature that is predicted to deteriorate the components of the intake system. .

<Modification of Embodiment>
The control structure of the program executed by ECU 400 may be modified as shown in the flowchart of FIG. In the flowchart shown in FIG. 10, the same steps as those in the flowchart shown in FIG. 8 are given the same step numbers. The processing is the same for them. Therefore, detailed description thereof will not be repeated here.

  In S300, ECU 400 calculates required throttle opening B based on the engine required power. In S302, ECU 400 controls throttle motor 112 so that the opening degree of throttle valve 114 becomes an opening degree corresponding to required throttle opening degree B.

  In this way, when the engine water temperature exceeds threshold value α and the engine required power is limited (YES in S204, S206), the required throttle opening decreases according to the limited engine required power (S300). ). Thereby, the opening degree of throttle valve 114 decreases (S302), and the intake air amount of engine 100 decreases. Therefore, the amount of heat generated in engine 100 can be reduced and the temperature increase of the reflux gas can be suppressed.

  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 figure which shows the structure of the vehicle by which the cooling control apparatus which concerns on embodiment of this invention is mounted. It is a figure which shows the motive power division mechanism mounted in the vehicle which concerns on embodiment of this invention. It is an alignment chart which shows the relationship of the rotation speed of the engine, MG (1), and MG (2) mounted in the vehicle which concerns on embodiment of this invention. It is a figure which shows the structure of the engine which concerns on embodiment of this invention. It is a figure which shows the structure of the cooling circuit of the engine which concerns on embodiment of this invention. It is a functional block diagram of the cooling control apparatus which concerns on embodiment of this invention. It is a flowchart (the 1) which shows the control structure of ECU which comprises the cooling control apparatus which concerns on embodiment of this invention. It is a flowchart (the 2) which shows the control structure of ECU which comprises the cooling control apparatus which concerns on embodiment of this invention. It is a timing chart of the temperature of the recirculation gas controlled by the cooling control device concerning an embodiment of the invention. It is a flowchart which shows the control structure of ECU which comprises the cooling control apparatus which concerns on the modification of embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Hybrid vehicle, 12 Drive wheel, 14 Reducer, 16 Drive shaft, 100 Engine, 102 Crankshaft, 110 Intake pipe, 112 Throttle motor, 114 Throttle valve, 118 Vacuum sensor, 120 Exhaust pipe, 122 Three-way catalytic converter, 124 Engine water temperature sensor, 130 EGR pipe, 132 EGR valve, 134 EGR cooler, 140 radiator, 142, 144, 146 Cooling water passage, 150 Thermostat, 152 Bypass passage, 160 Water pump, 200 Power split mechanism, 202 Sun gear, 204 Pinion gear, 206 Carrier, 208 Ring gear, 212 Output shaft, 300 Motor generator, 300A MG (1), 300B MG (2), 310 Traveling battery , 320 Boost converter, 330 Inverter, 340 Monitoring unit, 400 ECU, 402 MG_ECU, 404 HV_ECU, 406 Engine ECU, 410 Abnormality detection unit, 420 Flow rate calculation unit, 430 W / P control unit, 440 Engine required power calculation unit, 450 Target engine speed calculation unit, 460 MG (1) control unit.

Claims (10)

Provided in a vehicle having an internal combustion engine and a rotating electrical machine connected to the internal combustion engine as a power source, and from the exhaust pipe via a recirculation passage communicating the exhaust pipe of the internal combustion engine and the intake pipe of the internal combustion engine A cooling control apparatus for reflux gas to be returned to the intake pipe, wherein a reflux valve for adjusting a flow rate of the reflux gas and cooling water for the internal combustion engine are circulated in the vehicle, and a part of the reflux passage is provided. A cooling water pipe abutting with the pump, and a pump mechanism for adjusting the flow rate of the cooling water,
The cooling control device includes:
Means for calculating a required power of the internal combustion engine based on the state of the vehicle;
Means for determining whether or not the reflux valve is in an abnormal state that opens larger than a target value;
A pump control means for controlling the pump mechanism so that the flow rate of the cooling water is increased when the abnormal state is greater than when the abnormal state is not;
A reducing means for reducing the required power compared to a case where a predetermined condition relating to the temperature of the reflux gas is not satisfied,
A cooling control device including control means for controlling at least one of the internal combustion engine and the rotating electric machine so as to reduce the amount of heat generated in the internal combustion engine when the required power is reduced by the reduction means. .   The cooling according to claim 1, wherein the predetermined condition is a condition that when the flow rate of the cooling water is increased by the pump control means, the temperature of the cooling water is higher than a predetermined temperature. Control device. The vehicle includes a power distribution mechanism connected to the internal combustion engine, the rotating electrical machine, and a drive shaft of the vehicle,
The cooling control device according to claim 1, wherein the control means includes means for controlling the rotating electrical machine so as to reduce the rotational speed of the internal combustion engine via the distribution mechanism. A throttle valve for adjusting the amount of air taken into the internal combustion engine is provided in the intake pipe,
The cooling control device according to claim 1 or 2, wherein the control means includes means for controlling the throttle valve so as to reduce the air amount. Provided in a vehicle having an internal combustion engine and a rotating electrical machine connected to the internal combustion engine as a power source, and from the exhaust pipe via a recirculation passage communicating the exhaust pipe of the internal combustion engine and the intake pipe of the internal combustion engine A method for controlling the cooling of the recirculated gas that is recirculated to the intake pipe, wherein a recirculation valve that adjusts the flow rate of the recirculated gas and cooling water of the internal combustion engine circulate in the vehicle, and a part of the recirculation passage A cooling water pipe abutting with the pump, and a pump mechanism for adjusting the flow rate of the cooling water,
The cooling control method includes:
Calculating a required power of the internal combustion engine based on the state of the vehicle;
Determining whether or not the reflux valve is in an abnormal state that opens larger than a target value;
A pump control step for controlling the pump mechanism so that the flow rate of the cooling water is increased in the abnormal state as compared with the case in which the abnormal state is not;
A reduction step of reducing the required power as compared to a case where a predetermined condition relating to the temperature of the reflux gas is not satisfied,
And a control step of controlling at least one of the internal combustion engine and the rotating electrical machine so as to reduce the amount of heat generated in the internal combustion engine when the required power is reduced in the reduction step.   The predetermined condition is a condition that, when the flow rate of the cooling water is increased in the pump control step, the temperature of the cooling water is higher than a predetermined temperature. Cooling control method. The vehicle includes a power distribution mechanism connected to the internal combustion engine, the rotating electrical machine, and a drive shaft of the vehicle,
The cooling control method according to claim 5 or 6, wherein the control step includes a step of controlling the rotating electrical machine so as to reduce the rotational speed of the internal combustion engine via the distribution mechanism. A throttle valve for adjusting the amount of air taken into the internal combustion engine is provided in the intake pipe,
The cooling control method according to claim 5 or 6, wherein the operation control step includes a step of controlling the throttle valve so as to reduce the amount of air.   The program for making a computer perform the control method in any one of Claims 5-8.   The recording medium which recorded the program for making a computer perform the control method in any one of Claims 5-8 so that computer reading was possible.

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