JP2016205200A - Control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device capable of restricting damage of an air-fuel ratio sensor even if a positive detection by the air-fuel ratio sensor is being carried out when fuel is ignited at an internal combustion engine.SOLUTION: This invention comprises: a first running mode executing part 31 for executing a first running mode in which fuel is ignited at an engine EG acting as an internal combustion engine; a second running mode executing part 32 for executing a second running mode for generating a torque at a motor generator MG acting as an electric motor under a state in which the combustion of fuel at the engine EG is stopped; and a scavenging mode executing part 35 for executing a scavenging mode for flowing air taken from outside to an inside part of an exhaust pipe to discharge residuals within the exhaust pipe together with the air after the mode is transferred from the first running mode to the second running mode and during execution of the second running mode.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a control apparatus for a hybrid vehicle having an internal combustion engine and an electric motor as drive sources, an exhaust pipe through which exhaust gas discharged from the internal combustion engine flows, and an air-fuel ratio sensor provided in the exhaust pipe. About.

  Due to increasing environmental awareness, an automobile that generates driving force using fossil fuel such as gasoline is being replaced by an electric vehicle that generates driving force using electric power. As one form of automobile in such an alternative process, an automobile called a hybrid vehicle using an internal combustion engine and an electric motor as driving sources is widespread.

  Patent Document 1 below describes a hybrid vehicle in which an air-fuel ratio sensor is provided in an exhaust pipe through which exhaust gas discharged from an internal combustion engine flows. In the hybrid vehicle, fuel combustion in the internal combustion engine is performed based on detection information of the air-fuel ratio sensor. Specifically, the hybrid vehicle performs feedback control such as the amount of fuel injected from the fuel injection valve and the ignition timing by the spark plug based on the air-fuel ratio detected by the air-fuel ratio sensor. As a result, the air-fuel ratio in the internal combustion engine is controlled to be the stoichiometric air-fuel ratio, and the internal combustion engine can be operated with high efficiency.

US Pat. No. 7,654,077

  Incidentally, an air-fuel ratio sensor having a heater is known. By heating the sensor element of the air-fuel ratio sensor with the heat generated by the heater, the sensor element is activated and the air-fuel ratio can be reliably detected.

  However, when an air-fuel ratio sensor having a heater is mounted on a hybrid vehicle in this way, there is a possibility that the air-fuel ratio cannot be detected properly. Hereinafter, this problem will be described in detail.

  The exhaust gas discharged from the internal combustion engine contains a large amount of moisture. Therefore, when the hybrid vehicle shifts from a state where the fuel is burned in the internal combustion engine to a state where the fuel is stopped in the internal combustion engine and is driven by the electric motor, moisture remains in the exhaust pipe. Become. While the combustion of the fuel in the internal combustion engine is stopped, detection by the air-fuel ratio sensor becomes unnecessary, and thus the heat generation of the heater is stopped.

  When the combustion of the fuel is not performed in the internal combustion engine, the high-temperature exhaust gas is not newly supplied to the exhaust pipe, so that the temperature of the exhaust pipe decreases. As a result, condensed water caused by the moisture contained in the exhaust gas described above is generated inside the exhaust pipe. This condensed water also adheres to the sensor element of the air-fuel ratio sensor.

  Thereafter, when the combustion of the fuel in the internal combustion engine is resumed, it is necessary to heat the sensor element by heating the heater in order to resume the control of the fuel injection valve and the like based on the detection information of the air-fuel ratio sensor. Here, if the condensed water adheres to the sensor element, there is a possibility that local thermal stress or strain is generated in the heated sensor element, resulting in damage.

  As a means for preventing the sensor element from being damaged, it is conceivable that the heater is not temporarily heated immediately after the combustion of the fuel in the internal combustion engine is restarted, or the amount of heat generated by the heater is reduced. That is, while the temperature of the exhaust pipe is low and adverse effects due to condensed water are concerned, the heat generation of the heater is suppressed, and after a predetermined time has elapsed from the restart of combustion, the heater sufficiently generates heat after the temperature of the exhaust pipe increases. That's it.

  However, when the heat generation of the heater is suppressed, the sensor element is not sufficiently heated, and there is a possibility that detection by the air-fuel ratio sensor cannot be performed or detection accuracy is lowered. For this reason, while suppressing the heat generation of the heater, there arises a new problem that an increase in harmful substances discharged from the internal combustion engine and a deterioration in drivability are concerned.

  The present invention has been made in view of such problems, and an object thereof is to suppress damage to the air-fuel ratio sensor while reliably performing detection by the air-fuel ratio sensor when fuel is burned in the internal combustion engine. It is an object of the present invention to provide a control device that can perform the above-described operation.

  In order to solve the above-described problems, a control apparatus according to the present invention uses an internal combustion engine (EG) and an electric motor (MG) as drive sources, and an exhaust pipe (23) for flowing exhaust gas exhausted from the internal combustion engine to the inside. And a control device (30) of a hybrid vehicle (100) having an air-fuel ratio sensor (25) provided in the exhaust pipe, wherein the first combustion engine generates a driving force by burning fuel in the internal combustion engine. A first travel mode execution unit (31) for executing a travel mode; and a second travel mode for executing a second travel mode in which a driving force is generated by the electric motor in a state where combustion of fuel in the internal combustion engine is stopped. An execution unit (32), an air-fuel ratio control unit (33) for controlling an air-fuel ratio in the internal combustion engine based on detection information of the air-fuel ratio sensor during execution of the first travel mode, and the air-fuel ratio sensor Yes A heater control section (34) for controlling the heat generation of the heater (252) and stopping the heat generation of the heater during execution of the second travel mode, and transition from the first travel mode to the second travel mode A scavenging mode for executing a scavenging mode in which air taken in from the outside is caused to flow inside the exhaust pipe and the residue inside the exhaust pipe is discharged together with the air during execution of the second traveling mode. An execution unit (35).

  In the present invention, the scavenging mode is executed after the transition from the first travel mode to the second travel mode and during the execution of the second travel mode. In the scavenging mode, air taken in from the outside is caused to flow inside the exhaust pipe, and the residue inside the exhaust pipe is discharged together with the air. Therefore, even when exhaust gas containing moisture remains inside the exhaust pipe due to fuel combustion in the first travel mode, it can be exhausted in the subsequent scavenging mode. As a result, it is possible to suppress the condensate from adhering to the air-fuel ratio sensor and to prevent damage to the air-fuel ratio sensor while reliably performing detection by the air-fuel ratio sensor.

  ADVANTAGE OF THE INVENTION According to this invention, when burning a fuel in an internal combustion engine, the control apparatus which can suppress the failure | damage of an air fuel ratio sensor can be provided, performing the detection by an air fuel ratio sensor reliably.

1 is a block diagram showing a hybrid vehicle equipped with an engine ECU according to an embodiment of the present invention. It is a schematic diagram which shows the structure of the engine of FIG. It is a block diagram which shows engine ECU of FIG. It is a time chart which shows the example of control by engine ECU of FIG. It is a flowchart which shows the flow of a process by engine ECU of FIG. It is a time chart which shows the example of control by engine ECU of FIG. It is a flowchart which shows the flow of a process by engine ECU of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

  First, a schematic configuration of a hybrid vehicle 100 equipped with an engine ECU 30 according to an embodiment of the present invention will be described with reference to FIG. Hybrid vehicle 100 is a vehicle having engine EG and motor generator MG as drive sources. FIG. 1 illustrates main elements constituting the hybrid vehicle 100 as blocks.

  The engine EG is an internal combustion engine that uses gasoline as fuel, as will be described later. When the engine EG is started with the assistance of an ISG (Integrated Starter Generator) 61, the supplied fuel is burned inside to generate torque. The torque is transmitted to the front wheels 64 and 64 via the drive shafts 62 and 62, so that the hybrid vehicle 100 travels. Engine EG operates based on a control signal received from engine ECU (Electronic Control Unit) 30. The ISG 61 operates based on a control signal received from the hybrid ECU 41.

  Motor generator MG is a synchronous motor generator in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator. The motor generator MG functions as an electric motor that rotates by receiving power supplied from the battery 43 that is a secondary battery and generates torque. The torque is transmitted to the rear wheels 48 and 48 via the drive shafts 47 and 47, so that the hybrid vehicle 100 travels. Motor generator MG is controlled by applying a three-phase alternating current from inverter 42.

  Further, when the hybrid vehicle 100 travels by inertia and the rotor is rotated by an external force transmitted via the rear wheels 48 and 48 and the drive shafts 47 and 47, the motor generator MG is provided at both ends of the stator coil. It functions as a generator that generates electromotive force to generate electric power. The battery 43 can be charged with the electric power.

  Electric power is transferred between battery 43 and motor generator MG through inverter 42. The inverter 42 is a converter that converts DC power into AC power or AC power into DC power. Specifically, inverter 42 converts the DC power released by battery 43 into AC power, supplies the AC power to motor generator MG, and causes motor generator MG to generate torque. Inverter 42 also converts AC power generated by motor generator MG into DC power and supplies it to battery 43 to charge battery 43. The charge amount of the battery 43 is detected by the battery charge amount detector 44.

  The hybrid ECU 41 is an electronic device that operates in cooperation with the engine ECU 30. Based on the detection result of the battery charge amount detector 44, the hybrid ECU 41 transmits a control signal to the inverter 42 to control charging / discharging in the battery 43.

  Next, the configuration of the engine EG will be described with reference to FIG.

  The engine EG is a port injection internal combustion engine and has a plurality of cylinders 50. In FIG. 2, only one cylinder 50 is shown for convenience, but a plurality of cylinders 50 are actually arranged side by side in the depth direction of the drawing. A piston 56 that reciprocates in the vertical direction is disposed inside each cylinder 50. A combustion chamber 54 is formed between the upper inner wall surface of each cylinder 50 and the piston 56. The engine EG includes an intake pipe 12 that is connected to the intake port 51 and sucks combustion air from the outside, and an exhaust pipe 23 that is connected to the exhaust port 52 and guides exhaust gas discharged from the engine EG to the outside. ing.

  A filter-like air cleaner 13 that removes foreign matters from the passing air is provided at the most upstream portion of the intake pipe 12. An air flow sensor 14 that detects the flow rate of the air flowing through the flow path inside the intake pipe 12 is provided on the downstream side of the air cleaner 13.

  A throttle valve 16 that opens and closes the flow path inside the intake pipe 12 is provided on the downstream side of the air flow sensor 14. The throttle valve 16 is driven by a throttle motor 15, and its opening (throttle opening) can be adjusted. The throttle opening is detected by a throttle opening sensor 17.

  A surge tank 18 is provided on the downstream side of the throttle valve 16. The surge tank 18 is provided with an intake pipe pressure sensor 19 for detecting the intake pipe pressure. An intake manifold 20 that introduces air into each cylinder 50 is connected between the surge tank 18 and the intake port 51 of each cylinder 50.

  The engine EG has an intake valve 57 that opens and closes between the intake port 51 and the combustion chamber 54. The engine EG also has an exhaust valve 58 that opens and closes between the exhaust port 52 and the combustion chamber 54. The intake valve 57 is provided with a variable valve timing mechanism 59 for adjusting the valve timing. The exhaust valve 58 is provided with a variable valve timing mechanism 60 that adjusts the valve timing.

  A fuel injection valve 21 is attached in the vicinity of the intake valve 57 of each cylinder 50 of the engine EG so as to face the intake port 51. The fuel injection valve 21 injects fuel (gasoline) supplied from a fuel tank (not shown) to the intake port 51 in each cylinder 50.

  On the other hand, the exhaust pipe 23 of the engine EG is provided with a catalyst unit 27 for purifying exhaust gas generated by fuel combustion in the cylinder 50. Further, on the upstream side of the catalyst unit 27, an exhaust temperature sensor 24 for detecting the temperature of the exhaust gas flowing inside the exhaust pipe 23 is provided. An air-fuel ratio sensor 25 that detects the air-fuel ratio of the exhaust gas flowing in the exhaust pipe 23 is provided upstream of the catalyst unit 27 and downstream of the exhaust temperature sensor 24. The air-fuel ratio sensor 25 has a built-in sensor element 251 and a heater 252 that generates heat and heats the sensor element 251 by receiving power from the outside.

  A spark plug 53 is provided above the combustion chamber 54 in each cylinder 50. The spark plug 53 is provided for each cylinder 50 and is provided such that the lower end thereof faces the combustion chamber 54. The spark plug 53 has an electrode at its lower end. The spark plug 53 is supplied with electric power from the outside, thereby generating spark discharge at its electrode and igniting, thereby igniting the mixture of fuel gas and air in each cylinder 50.

  A cooling water temperature sensor 26, an oil temperature sensor 28, and a crank angle sensor 29 are attached to the cylinder block of the engine EG. The coolant temperature sensor 26 detects the temperature of coolant that flows through the cylinder block and cools the engine EG, and outputs a signal corresponding to the detected value. The oil temperature sensor 28 detects the temperature of the lubricating oil sealed in the cylinder block and outputs a signal corresponding to the detected value. The crank angle sensor 29 detects the rotation of the crankshaft of the engine EG for each predetermined crank angle and outputs a signal corresponding to the detected value.

  Next, the engine ECU 30 will be described with reference to FIG. The engine ECU 30 is partially or entirely configured by an analog circuit or a digital processor. In any case, in order to fulfill the function of outputting a control signal based on the received signal, a functional control block is configured in the engine ECU.

  FIG. 3 shows the engine ECU as a functional control block diagram. Note that the software module incorporated in the analog circuit or digital processor constituting the engine ECU does not necessarily have to be divided into the control blocks shown in FIG. 1, and is configured to function as a plurality of control blocks. However, it may be further subdivided. A person skilled in the art can appropriately change the actual configuration inside the engine ECU as long as the processing described later can be executed.

  The engine ECU 30 is electrically connected to the hybrid ECU 41 and can communicate with each other. The engine ECU 30 includes various sensors such as an air flow sensor 14, a throttle opening sensor 17, an intake pipe pressure sensor 19, an exhaust gas temperature sensor 24, an air-fuel ratio sensor 25, a coolant temperature sensor 26, an oil temperature sensor 28, and a crank angle sensor 29. It is electrically connected and receives signals output from various sensors. Further, the engine ECU 30 is also electrically connected to the throttle motor 15, the fuel injection valve 21, the spark plug 53, and the heater 252 of the air-fuel ratio sensor 25, and controls each element by transmitting a control signal. In the present application, “electrically connected” is not limited to the state of being connected by wire, and may include a state in which communication is possible with each other wirelessly.

  Further, the engine ECU 30 includes a first travel mode execution unit 31, a second travel mode execution unit 32, an air-fuel ratio control unit 33, a heater control unit 34, a scavenging mode execution unit 35, and an exhaust gas temperature acquisition unit 36. And an engine temperature acquisition unit 37 and a charge amount acquisition unit 38.

  The first travel mode execution unit 31 is a portion that executes a “first travel mode” in which the engine EG burns fuel to generate torque. That is, the first travel mode execution unit 31 causes the fuel injection valve 21 to inject fuel and ignites the air-fuel mixture with the spark plug 53. As a result, the so-called intake stroke, compression stroke, combustion stroke, and exhaust process are repeatedly performed at different phases in each cylinder 50, and torque is generated.

  The second travel mode execution unit 32 is a portion that executes a “second travel mode” in which torque is generated in the motor generator MG while the combustion of fuel in the engine EG is stopped. That is, the second travel mode execution unit 32 stops the fuel injection of the fuel injection valve 21 and supplies electric power to the motor generator MG to generate torque.

  The air-fuel ratio control unit 33 is a part that controls the air-fuel ratio of the mixture of fuel and air in each cylinder 50. Specifically, the air-fuel ratio control unit 33 is injected from the fuel injection valve 21 based on the detection information of the air-fuel ratio sensor 25 so that the air-fuel ratio of the air-fuel mixture in each cylinder 50 becomes the stoichiometric air-fuel ratio. Feedback control such as the amount of fuel, the injection timing, the number of injections, and the ignition timing by the spark plug 53 is performed.

  The heater control unit 34 is a part that controls the heat generation of the heater 252 built in the air-fuel ratio sensor 25. Specifically, the heater control unit 34 controls the amount of heat generated by the heater 252 by appropriately changing the duty of the heater 252.

  The scavenging mode execution unit 35 flows the air taken in from the outside into the exhaust pipe 23 after the transition from the first travel mode to the second travel mode and during the execution of the second travel mode. 23 is a portion that executes a scavenging mode in which the residue inside 23 is discharged together with the air. Specific modes of the scavenging mode will be described later.

  The exhaust gas temperature acquisition unit 36 is a part that acquires the temperature of the exhaust gas flowing inside the exhaust pipe 23. Specifically, the exhaust gas temperature acquisition unit 36 acquires the temperature of the exhaust gas by performing a predetermined calculation based on a signal received from the exhaust temperature sensor 24.

  The engine temperature acquisition unit 37 is a part that acquires the temperature of the engine EG. Specifically, the engine temperature acquisition unit 37 performs a predetermined calculation based on a signal received from the coolant temperature sensor 26, and estimates the temperature of the engine EG. The engine temperature acquisition unit 37 performs a predetermined calculation based on a signal received from the oil temperature sensor 28 in place of or in addition to the signal received from the coolant temperature sensor 26, and determines the temperature of the engine EG. It may be estimated.

  The charge amount acquisition unit 38 is a part that acquires the charge amount of the battery 43. Specifically, the charge amount acquisition unit 38 acquires the charge amount of the battery 43 based on a signal received from the battery charge amount detector 44.

  Next, an example of control by the engine ECU 30 will be described with reference to FIG. In the following, for the sake of simplicity, a detailed description will be given assuming that the processing performed by each part such as the first traveling mode execution unit 31 of the engine ECU 30 is also performed by the engine ECU 30 as a whole.

  At time t11, the engine ECU 30 starts executing the first travel mode. That is, the engine ECU 30 opens and closes the intake valve 57 and the exhaust valve 58 and injects fuel by the fuel injection valve 21 to start combustion of the fuel in the cylinder 101. As a result, the rotational speed of the engine EG increases and torque is generated, the hybrid vehicle 100 starts to travel and the vehicle speed increases, and the temperature of the exhaust gas that is discharged from the engine EG and flows through the exhaust pipe 23 Also rises. Further, in the first travel mode, the duty is increased to 100% and the heater 252 of the air-fuel ratio sensor 25 is caused to generate heat. Thereby, the sensor element 251 is heated and activated, and feedback control based on the detection information of the air-fuel ratio sensor 25 can be performed.

  At time t12, the engine ECU 30 shifts from the first travel mode to the second travel mode. That is, engine ECU 30 stops fuel injection from fuel injection valve 21 and supplies electric power to motor generator MG to generate torque. As a result, hybrid vehicle 100 starts traveling using only the torque generated by motor generator MG. The hybrid vehicle 100 takes in air from the outside by this traveling.

  Further, at time t12, the engine ECU 30 starts executing the scavenging mode. In the scavenging mode, the intake valve 57 and the exhaust valve 58 are opened. As a result, the air taken in by the hybrid vehicle 100 is introduced into the cylinder 50 through the intake pipe 12, and passes through the cylinder 50 and is supplied into the exhaust pipe 23.

  Incidentally, the exhaust gas discharged by the engine EG during execution of the first travel mode contains a large amount of moisture. Therefore, when the first travel mode is shifted to the second travel mode, moisture remains in the exhaust pipe 23. For this reason, when the temperature of the exhaust pipe 23 decreases, condensed water W (see FIG. 2) is generated inside the exhaust pipe 23, which may cause a failure of the air-fuel ratio sensor 25 and the like.

  On the other hand, the engine ECU 30 executes the scavenging mode and discharges the exhaust gas remaining in the exhaust pipe 23 by the air taken in from the outside. As a result, it is possible to suppress the condensed water from adhering to the air-fuel ratio sensor 25 and to prevent the air-fuel ratio sensor from being damaged.

  When the temperature of the exhaust gas flowing through the exhaust pipe 23 becomes 100 ° C. or lower at time t13, the engine ECU 30 ends the scavenging mode. That is, the engine ECU 30 determines that exhaust of the residue has been completed when the air taken in from the outside flows and the temperature of the exhaust gas flowing through the exhaust pipe 23 has become the threshold value of 100 ° C. or less, and the intake air is exhausted. The valve 57 and the exhaust valve 58 are closed, and the intake of air into the exhaust pipe 23 is stopped. The exhaust gas temperature of 100 ° C. is a predetermined threshold value.

  At time t14, the engine ECU 30 increases the duty to 100% and causes the heater 252 of the air-fuel ratio sensor 25 to generate heat. Thereby, the sensor element 251 is heated and activated, and detection by the air-fuel ratio sensor 25 becomes possible.

  At time t15, the engine ECU 30 starts executing the first travel mode again. That is, the engine ECU 30 opens and closes the intake valve 57 and the exhaust valve 58 and injects fuel by the fuel injection valve 21 to start combustion of the fuel in the cylinder 101. Hybrid vehicle 100 travels with torque generated by engine EG. The engine ECU 30 can perform feedback control based on the detection information of the air-fuel ratio sensor 25 in the first traveling mode.

  Next, the flow of processing executed in the engine ECU 30 will be described with reference to FIG. The flowchart shown in FIG. 5 is executed by the engine ECU 30 at a predetermined cycle after the transition from the first travel mode to the second travel mode and during the execution of the second travel mode.

  First, the engine ECU 30 determines whether or not the temperature of the exhaust gas flowing through the exhaust pipe 23 is higher than 100 ° C. in step S11 of FIG. When it determines with the temperature of exhaust gas not being higher than 100 degreeC (S11: No), engine ECU30 complete | finishes a process. On the other hand, when it determines with the temperature of exhaust gas being higher than 100 degreeC (S11: Yes), engine ECU30 progresses to the process of step S12.

  Next, the engine ECU 30 stops energizing the heater 252 in step S12. That is, the duty of the heater 252 is set to 0% and the heat generation is stopped.

  Next, the engine ECU 30 opens the intake valve 57 and the exhaust valve 58 in step S13. Thereby, the air taken in from the outside is caused to flow into the exhaust pipe 23, and the scavenging mode in which the residue inside the exhaust pipe 23 is discharged together with the air is executed.

  Next, engine ECU30 determines whether the temperature of the exhaust gas which flows through the inside of the exhaust pipe 23 is 100 degrees C or less by step S14. When it determines with the temperature of exhaust gas not being 100 degrees C or less (S14: No), engine ECU30 continues and performs scavenging mode. On the other hand, when it determines with the temperature of exhaust gas being 100 degrees C or less (S14: Yes), engine ECU30 progresses to the process of step S15.

  Next, the engine ECU 30 closes the intake valve 57 and the exhaust valve 58 in step S15. Thereby, the intake of air into the exhaust pipe 23 is stopped, and the execution of the scavenging mode ends.

  Next, engine ECU30 starts energization of heater 252 at Step S16. That is, the heating of the heater 252 is set to 100% and the heat generation is started.

  As described above, in the present embodiment, the scavenging mode is executed after the transition from the first running mode to the second running mode and during the execution of the second running mode. In the scavenging mode, air taken in from the outside is caused to flow inside the exhaust pipe 23, and the residue inside the exhaust pipe 23 is discharged together with the air. Therefore, even when exhaust gas containing moisture remains inside the exhaust pipe 23 due to fuel combustion in the first travel mode, these can be exhausted in the subsequent scavenging mode. As a result, it is possible to suppress breakage of the air-fuel ratio sensor 25 while suppressing the condensed water from adhering to the air-fuel ratio sensor 25 and reliably performing detection by the air-fuel ratio sensor 25.

  In the present embodiment, the exhaust gas temperature acquisition unit 36 that acquires the temperature of the exhaust gas flowing through the exhaust pipe 23 is provided, and the scavenging mode execution unit 35 determines the temperature acquired by the exhaust gas temperature acquisition unit 36 in advance. The scavenging mode is executed until the temperature reaches 100 ° C. or lower. When the air taken in from the outside by execution of the scavenging mode flows through the exhaust pipe 23, the temperature of the exhaust gas flowing through the exhaust pipe 23 decreases accordingly. In the present embodiment, it is possible to determine the progress of the discharge of the residue based on the temperature drop of the exhaust gas, and to execute the scavenging mode until the residue is reliably discharged.

  Further, the heater control unit 34 stops the heat generation of the heater 252 until the temperature acquired by the exhaust gas temperature acquisition unit 36 becomes 100 ° C. or less. As a result, in the second traveling mode that does not require the detection information of the air-fuel ratio sensor 25, it is possible to suppress power consumption.

  Next, another example of control by the engine ECU 30 will be described with reference to FIG.

  At time t21, the engine ECU 30 starts executing the first travel mode. That is, the engine ECU 30 opens and closes the intake valve 57 and the exhaust valve 58 and injects fuel by the fuel injection valve 21 to start combustion of the fuel in the cylinder 101. As a result, the rotational speed of the engine EG increases and torque is generated, the hybrid vehicle 100 starts to travel and the vehicle speed increases, and the temperature of the exhaust gas that is discharged from the engine EG and flows through the exhaust pipe 23 Also rises. Further, in the first travel mode, the duty is increased to 100% and the heater 252 of the air-fuel ratio sensor 25 is caused to generate heat. Thereby, the sensor element 251 is heated and activated, and feedback control based on the detection information of the air-fuel ratio sensor 25 can be performed.

  At time t22, the engine ECU 30 shifts from the first travel mode to the second travel mode. That is, engine ECU 30 stops fuel injection from fuel injection valve 21 and supplies electric power to motor generator MG to generate torque. As a result, hybrid vehicle 100 starts traveling using only the torque generated by motor generator MG. The hybrid vehicle 100 takes in air from the outside by this traveling.

  Further, at time t22, the engine ECU 30 starts executing the scavenging mode. In the scavenging mode, the intake valve 57 and the exhaust valve 58 are opened. As a result, the air taken in by the hybrid vehicle 100 is introduced into the cylinder 50 through the intake pipe 12, and passes through the cylinder 50 and is supplied into the exhaust pipe 23.

  At time t23, the engine ECU 30 switches from the second travel mode to the first travel mode based on the fact that the temperature of the engine EG has become 300 ° C. or lower or the charge amount of the battery 43 has decreased to 0.2 kWh. At the same time, the scavenging mode is terminated. That is, the engine ECU 30 opens and closes the intake valve 57 and the exhaust valve 58 even when the temperature of the exhaust gas flowing inside the exhaust pipe 23 is higher than 100 ° C. and the discharge of the residue is not completed. At the same time, fuel is injected by the fuel injection valve 21 and combustion of the fuel in the cylinder 101 is started. The temperature of the engine EG of 300 ° C. and the charge amount of the battery 43 of 0.2 kWh are predetermined threshold values.

  At time t24, the engine ECU 30 increases the duty to 100% and causes the heater 252 of the air-fuel ratio sensor 25 to generate heat based on the fact that the temperature of the engine EG becomes 500 ° C. or higher. Thereby, the sensor element 251 is heated and activated, and detection by the air-fuel ratio sensor 25 becomes possible.

  Next, the flow of processing executed in the engine ECU 30 will be described with reference to FIG. The flowchart shown in FIG. 7 is executed by the engine ECU 30 at a predetermined cycle during the execution of the scavenging mode.

  First, the engine ECU 30 determines whether or not the temperature of the engine EG is 300 ° C. or lower in step S21 of FIG. When it determines with the temperature of engine EG being 300 degrees C or less (S21: Yes), engine ECU30 progresses to the process of step S23. On the other hand, when it determines with the temperature of engine EG not being 300 degrees C or less (S21: No), engine ECU30 progresses to the process of step S22.

  Next, engine ECU30 determines whether the charge amount of the battery 43 is 0.2 kWh or less in step S22. When it determines with the charge amount of the battery 43 not being 0.2 kWh or less (S22: No), engine ECU30 complete | finishes a process. On the other hand, when it determines with the charge amount of the battery 43 being 0.2 kWh or less (S22: Yes), engine ECU30 progresses to the process of step S23.

  Next, engine ECU30 starts execution of the 1st run mode at Step S23. That is, the second traveling mode that has been executed so far is shifted to the first traveling mode, and the scavenging mode is terminated accordingly.

  Next, engine ECU30 determines whether the temperature of engine EG is 500 degreeC or more by step S24. If it is determined that the temperature of the engine EG is not 500 ° C. or higher (S24: No), the engine ECU 30 continues to execute the first travel mode. On the other hand, when it determines with the temperature of engine EG being 500 degreeC or more (S24: Yes), engine ECU30 progresses to the process of step S25. The engine EG temperature of 500 ° C. is a predetermined threshold value.

  Next, the engine ECU 30 starts energization of the heater 252 in step S25. That is, the heating of the heater 252 is set to 100% and the heat generation is started.

  As described above, the present embodiment includes the engine temperature acquisition unit 37 that acquires the temperature of the engine EG. The scavenging mode execution unit 35 does not execute the scavenging mode when the temperature acquired by the engine temperature acquisition unit 37 is not more than a predetermined 300 ° C. When air taken in from the outside by execution of the scavenging mode flows through the exhaust pipe 23, the temperature of the engine EG decreases accordingly. In the present invention, when the temperature of the engine EG is 300 ° C. or lower, the scavenging mode is not executed, so that further temperature reduction of the engine EG is suppressed. It becomes possible to suppress the trouble caused by becoming.

  Moreover, in this embodiment, the charge amount acquisition part 38 which acquires the charge amount of the battery 43 which supplies electric power to the motor generator MG is provided. The scavenging mode execution unit 35 does not execute the scavenging mode when the charge amount of the battery 43 acquired by the charge amount acquisition unit 38 is 0.2 kWh or less determined in advance. That is, the engine ECU 30 does not execute the scavenging mode even when the charge amount of the battery 43 is not sufficient and it is difficult to travel the hybrid vehicle 100 by executing the second travel mode. Thereby, after the charge amount of the battery 43 becomes 0.2 kWh or less, the first traveling mode is executed, the electric power is generated in the motor generator MG, the battery 43 is charged, and the charge amount is recovered. Is possible.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. Each element included in each of the specific examples described above and their arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be appropriately changed.

23: Exhaust pipe 25: Air-fuel ratio sensor 30: Engine ECU (control device)
31: 1st driving mode execution part 32: 2nd driving mode execution part 33: Air fuel ratio control part 34: Heater control part 35: Scavenging mode execution part 36: Exhaust gas temperature acquisition part 37: Engine temperature acquisition part 38: Charge amount Acquisition unit 43: battery 100: hybrid vehicle 252: heater EG: engine (internal combustion engine)
MG: Motor generator (electric motor)

Claims (4)

An exhaust pipe (23) that uses an internal combustion engine (EG) and an electric motor (MG) as drive sources and flows exhaust gas exhausted from the internal combustion engine, and an air-fuel ratio sensor (25) provided in the exhaust pipe; A control device (30) for a hybrid vehicle (100) having
A first travel mode execution unit (31) for executing a first travel mode for generating driving force by burning fuel in the internal combustion engine;
A second travel mode execution unit (32) for executing a second travel mode in which driving force is generated by the electric motor in a state where combustion of fuel in the internal combustion engine is stopped;
An air-fuel ratio control unit (33) for controlling an air-fuel ratio in the internal combustion engine based on detection information of the air-fuel ratio sensor during execution of the first travel mode;
A heater control section (34) for controlling the heat generation of the heater (252) of the air-fuel ratio sensor and stopping the heat generation of the heater during the execution of the second travel mode;
After the transition from the first travel mode to the second travel mode, during the execution of the second travel mode, the air taken in from the outside is caused to flow inside the exhaust pipe to remain in the exhaust pipe. A scavenging mode execution unit (35) for executing a scavenging mode for discharging an object together with the air. An exhaust gas temperature acquisition unit (36) for acquiring the temperature of the exhaust gas flowing through the exhaust pipe;
2. The control device according to claim 1, wherein the scavenging mode execution unit executes the scavenging mode until the temperature acquired by the exhaust gas temperature acquisition unit is equal to or lower than a predetermined first predetermined value. An internal combustion engine temperature acquisition unit (37) for acquiring the temperature of the internal combustion engine;
The control according to claim 2, wherein the scavenging mode execution unit does not execute the scavenging mode when the temperature acquired by the internal combustion engine temperature acquisition unit is equal to or lower than a predetermined second predetermined value. apparatus. A charge amount acquisition unit (38) for acquiring a charge amount of a battery that supplies power to the electric motor;
The scavenging mode execution unit does not execute the scavenging mode when the charge amount of the battery acquired by the charge amount acquisition unit is equal to or less than a predetermined third predetermined value. The control device described.

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