JP2023173056A - Gas sensor control device and heating control method - Google Patents

Abstract

An object of the present invention is to provide a gas sensor control device, etc. for a hybrid vehicle, which can suppress power consumption of a heater of a gas sensor when driving in a motor driving mode. A gas sensor control device 1 that is attached to an exhaust pipe 208 of an engine 201 in a hybrid vehicle 200 and that controls a gas sensor 2 that has a detection cell 51 that detects the concentration of a specific gas and a heater 83 that heats the detection cell 51. A first determination unit that determines whether the driving mode is an engine driving mode or a motor driving mode that uses only the driving force of the motor 202, and a first determination unit that determines whether the charge level of the battery 204 exceeds a first threshold α. and a second determination section that determines the activation temperature of the heater 83, when the first determination section determines that the mode is motor running mode and the second determination section determines that the mode is higher than the first threshold value α. The energization of the heater 83 is controlled in either a standby mode in which the heater 83 generates heat at a lower standby temperature, or a stop mode in which the energization of the heater 83 is stopped. [Selection diagram] Figure 1

Description

The present invention relates to a gas sensor control device and a heating control method.

A hybrid vehicle is a vehicle that includes an engine and a motor with a power generation function as a driving force source. The driving modes of such hybrid vehicles include a motor driving mode in which the vehicle is driven only by the driving force of the motor, and an engine driving mode which mainly utilizes the driving force of the engine. It can be switched as appropriate. For example, when the required driving force is small, the hybrid vehicle runs in motor drive mode. Furthermore, if the required driving force increases due to, for example, the accelerator pedal being depressed while in the motor drive mode, the hybrid vehicle runs in the engine drive mode.

By the way, a gas sensor is attached to the exhaust pipe of the engine in a hybrid vehicle. The gas sensor detects the concentration of a specific gas contained in the gas flowing in the exhaust pipe for feedback control of the air-fuel ratio, etc., and uses a solid electrolyte body (for example, a zirconia-based material such as partially stabilized zirconia). and a pair of electrodes, a detection cell including a pair of electrodes, and a heater that heats the detection cell. The detection cell needs to be maintained at a predetermined temperature (for example, 600 to 700° C.) in order to be activated by being heated by a heater so that the concentration of a specific gas and the like can be detected with high accuracy.

Furthermore, Patent Document 1 discloses a technology that aims to reduce the burden on the battery by stopping the power supply to the heater of the gas sensor and suppressing the power consumption of the heater when the engine is automatically stopped during a primary stop such as waiting at a traffic light. is listed.

Japanese Patent Application Publication No. 2014-16317

Conventionally, in a hybrid vehicle, technology for suppressing power consumption of a gas sensor heater when driving in a motor driving mode has not been sufficiently studied.

SUMMARY OF THE INVENTION An object of the present invention is to provide a gas sensor control device and the like for a hybrid vehicle that can suppress power consumption of a heater of a gas sensor when driving in a motor driving mode.

Means for solving the above problem are as follows. That is,
<1> A hybrid vehicle equipped with an engine and a motor with a power generation function as a driving force source, and a battery that supplies electric power to the motor or stores electric power from the motor. A gas sensor control device that controls a gas sensor that has a detection cell that detects concentration and a heater that heats the detection cell, and controls energization of the heater and sets the driving mode of the hybrid vehicle to a driving force of the engine. and a heater control unit that causes the heater to generate heat at an activation temperature that makes the detection cell in a detectable state when the engine is running in the engine running mode. mode or a motor drive mode that utilizes only the driving force of the motor, and a second determination unit that determines whether the charge level of the battery exceeds a first threshold α. , the heater control unit is configured to operate the heater at a temperature lower than the activation temperature when the first determination unit determines that the motor running mode is set and the second determination unit determines that the motor running mode is higher than the first threshold α. A gas sensor control device that controls energization of the heater in either a standby mode that generates heat at a standby temperature or a stop mode that stops energization of the heater.

<2> The gas sensor control device according to <1>, wherein the heater control unit controls energization of the heater by selecting either the standby mode or the stop mode according to the charge level of the battery. .

<3> When the charge level of the battery falls below a second threshold β (however, β>α) while in the stop mode, the heater control unit switches to the standby mode and controls the energization of the heater. The gas sensor control device according to <1> or <2> above.

<4> When the charge level of the battery exceeds a third threshold γ (where γ>β) in the standby mode, the heater control unit switches to the stop mode and controls the energization of the heater. The gas sensor control device according to <1> or <2> above.

<5> A hybrid vehicle that is equipped with an engine and a motor with a power generation function as a driving force source, and a battery that supplies electric power to the motor or stores electric power from the motor, and that is attached to the exhaust pipe of the engine and that generates a specific gas. A gas sensor having a detection cell that detects concentration and a heater that heats the detection cell; and a gas sensor that controls energization of the heater, and that the driving mode of the hybrid vehicle is an engine driving mode that utilizes the driving force of the engine. and a heater control unit that causes the heater to generate heat at an activation temperature that makes the detection cell in a detectable state, wherein the running mode is the engine running mode or the a first determination step of determining whether the mode is a motor drive mode that utilizes only the driving force of the motor; a second determination step of determining whether the charge level of the battery exceeds a first threshold α; and the first determination step. a standby mode in which the heater generates heat at a standby temperature lower than the activation temperature when the determination result is the motor running mode and it is determined in the second determination step that it exceeds the first threshold α; A heating control method comprising: an energization control step in which the heater control section controls energization of the heater in any of the stop modes in which energization of the heater is stopped.

<6> In the energization control step, the heater control section performs energization control of the heater by selecting either the standby mode or the stop mode according to the charge level of the battery. The heating control method described.

<7> In the energization control step, when the charge level of the battery falls below a second threshold β (where β>α) while in the stop mode, the heater control unit switches to the standby mode. The heating control method according to <5> or <6>, wherein energization control of the heater is performed.

<8> In the energization control step, when the charge level of the battery exceeds a third threshold γ (where γ>β) in the standby mode, the heater control section switches to the stop mode. The heating control method according to <5> or <6>, wherein the heater is energized by controlling the heater.

According to the present invention, it is possible to provide a gas sensor control device and the like for a hybrid vehicle, which can suppress the power consumption of the heater of the gas sensor when traveling in the motor driving mode.

An explanatory diagram showing a schematic configuration of a hybrid vehicle including a gas sensor control device according to Embodiment 1 Block diagram showing an example of the functional configuration of a microcontroller Flowchart showing processing related to heater energization control executed by the microcomputer An explanatory diagram showing the relationship between the battery charge level and the driving mode and the relationship between the battery charge level and the heater control mode in a hybrid vehicle.

<Embodiment 1>
Hereinafter, a gas sensor control device 1 and a heating control method according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is an explanatory diagram showing a schematic configuration of a hybrid vehicle 200 including a gas sensor control device 1 according to the first embodiment. Here, first, hybrid vehicle 200 will be explained.

A hybrid vehicle (hereinafter sometimes referred to as "HV vehicle") 100, as shown in FIG. 1, includes an engine 201 as a driving force source and a motor 202 with a power generation function. The HV vehicle 200 has two driving modes: a motor driving mode in which the vehicle is driven only by the driving force of the motor 202, and an engine driving mode which mainly utilizes the driving force of the engine 201. Accordingly, switching between these driving modes (motor driving mode, engine driving mode) is performed as appropriate.

In addition to an engine 201 and a motor 202, the HV vehicle 200 includes an inverter 203, a battery 204, a power transmission system 205, drive wheels 206, an ECU 207, and the like, as shown in FIG. Note that in this specification, the configuration of HV vehicle 200 is simplified for convenience of explanation. Therefore, HV vehicle 200 may be provided with other components other than those shown in FIG. 1 as appropriate.

The engine 201 is an internal combustion engine that generates power using gasoline or the like as fuel, and is, for example, a four-cylinder gasoline engine. A spark plug is arranged for each cylinder of the engine 201. Furthermore, an air cleaner, an intake pipe, and an intake manifold are provided on the upstream side of the engine 201. The intake pipe is provided with a throttle valve that adjusts the amount of intake air. The intake manifold is provided with a fuel injection valve that injects fuel into each cylinder. Note that in other embodiments, the engine may be a direct injection engine in which the fuel injection valve is provided in the combustion chamber instead of in the intake manifold.

An exhaust manifold and an exhaust pipe 208 (not shown) are provided downstream of the engine 201. One end of the exhaust pipe 208 is connected to an exhaust manifold, and the other end of the exhaust pipe 208 is connected to a catalyst device (three-way catalyst). Exhaust gas discharged from the exhaust port of the engine 201 is guided to the exhaust pipe 208 via the exhaust manifold.

A crankshaft, which is the output shaft of the engine 201, is connected to the input side of a power transmission system 205, and the power output from the engine 201 is transmitted to the driving wheels via the power transmission system 205.

A gas sensor 2 is attached to the exhaust pipe 208 to detect the concentration of a specific gas (for example, oxygen gas) contained in the exhaust gas flowing inside the exhaust pipe 208 . Details of the gas sensor 2 will be described later.

The motor (motor with a power generation function) 202 is a motor generator that is regeneratively driven when the HV vehicle 200 decelerates and can generate power using the kinetic energy of the drive wheels 206. Electric power generated by motor 202 is supplied to battery 204 via inverter 203. Inverter 203 converts AC power generated by motor 202 into DC power, and the resulting DC power is supplied to battery 10 . Furthermore, the inverter 203 supplies power to the motor 202 through PWM control (that is, pulse width modulation control).

The battery 204 is a driving battery, and is made of a battery that can charge and discharge power (for example, a lithium ion battery, a lithium ion polymer battery, etc.). Battery 204 stores power supplied to motor 202.

The output side of the power transmission system 205 is connected to an axle of a drive wheel 206. Power output from the engine 201 or motor 202 is transmitted to drive wheels 206 via a power transmission system 205 and an axle. The power transmission system 205 includes a transmission, and the power output from the engine 201 or the motor 202 is changed in speed by the power transmission system 205 and transmitted to the drive wheels 206.

Note that in the HV vehicle 200, the driving wheels 206 to which the power (driving force) output from the driving force source (engine 201 or motor 202) is transmitted may be the front wheels or the rear wheels. . Further, the power output from the output side of the power transmission system 205 may be transmitted to both the front wheels and the rear wheels via a propeller shaft (not shown).

ECU (Electronic Control Unit) 207 is a computer that performs various controls in HV vehicle 200. The ECU 207 is equipped with computer hardware such as a processor and memory, and operates according to installed software such as an OS (Operating System) and application programs.

The ECU 207 is electrically connected to the fuel injection valve, the ignition circuit, the distributor, the control device 3 of the gas sensor control device 1, and the like. The ignition circuit is an electric circuit that generates a high voltage current that drives a spark plug based on a signal output from the ECU 207. The distributor distributes the high voltage current output from the ignition circuit to the spark plugs in synchronization with the crank angle. A rotation sensor that detects the crank angle (that is, detects the engine speed) is attached to the distributor. The control device 3 controls the operation of the gas sensor 2.

The ECU 207 executes various processes such as, for example, performing air-fuel ratio feedback control of the engine 201, and selecting and switching driving modes.

Next, the gas sensor control device 1 will be explained. The gas sensor control device 1 mainly includes a gas sensor 2 and a control device 3, as shown in FIG.

The gas sensor 2 is used for air-fuel ratio feedback control of the engine 201, and is a full-range air-fuel ratio sensor whose detection target gas is exhaust gas flowing in the exhaust pipe 208. The operation of the gas sensor 2 is controlled by a control device 3. Further, the gas sensor 2 operates using electric power from the battery 204 supplied via the ECU 207.

The gas sensor 2 includes a sensor element (detection cell) 51 that detects the concentration of oxygen gas (specific gas) contained in exhaust gas, a heater element 53 that heats the sensor element 51, a housing (not shown) that houses them, and the like. .

The sensor element 51 includes a structure in which solid electrolyte bodies 55 and 57 and insulating base bodies 59 and 61 are stacked. The solid electrolyte bodies 55 and 57 are formed of a material whose main component is partially stabilized zirconia (YSZ) using yttria as a stabilizer, and have oxygen ion conductivity. The insulating substrates 59 and 61 are formed of a material containing alumina as a main component. The heater element 53 is stacked on the sensor element 51 in order to activate the solid electrolyte bodies 55, 57 early, maintain stability of activation, etc.

In detail, the sensor element 51 includes a detection chamber 63, a diffusion rate limiting section 65, an oxygen pump cell (hereinafter sometimes referred to as an "Ip cell") 67, and an oxygen partial pressure detection cell (hereinafter referred to as a "Vs cell"). ) 69 and insulating bases 59 and 61.

The detection chamber 63 is a small space into which exhaust gas flowing in the exhaust pipe 208 is introduced. The diffusion rate controlling section 65 is formed of a porous member (for example, alumina), and adjusts the amount of exhaust gas introduced into the detection chamber 63 .

The Ip cell 67 includes a solid electrolyte body 55 and a pair of porous electrodes 71 and 73 formed so as to sandwich the solid electrolyte body 55 therebetween. These electrodes 71 and 73 are formed of a material containing platinum (Pt) as a main component, for example. In the Ip cell 67, by supplying a current between the electrodes 71 and 73, oxygen is pumped out and generated between the atmosphere (exhaust gas) in contact with the electrode 71 and the atmosphere (atmosphere inside the detection chamber 63) in contact with the electrode 73. Perform pumping (so-called oxygen pumping).

The insulating base 61 has an opening 75 at a position above the electrode 71. The opening 75 is provided with a porous protective layer 77 made of, for example, alumina.

The Vs cell 69 includes a solid electrolyte body 57 and a pair of porous electrodes 79 and 81 formed to sandwich the solid electrolyte body 57 therebetween. These electrodes 79 and 81 are formed of a material containing platinum (Pt) as a main component, for example. Of these, the electrode 79 is provided on the surface of the solid electrolyte body 57 on the detection chamber 63 side, and the electrode 81 is provided with an oxygen concentration that is a reference for detecting the oxygen concentration in the detection chamber 63. functions as an oxygen reference electrode to maintain

The Vs cell 69 mainly generates a voltage (electromotive force) depending on the oxygen partial pressure difference between the atmospheres separated by the solid electrolyte body 57 (the atmosphere in the detection chamber 63 in contact with the electrode 79 and the atmosphere in contact with the electrode 81). do.

The heater element 53 is an element that heats and activates the sensor element 51 (in particular, the solid electrolyte bodies 55 and 57), and includes a heater (heating resistor) 83 and insulating base bodies 85 and 87. The heater 83 is made of a material mainly composed of platinum. Heater 83 is sandwiched between insulating base 85 and insulating base 87. The insulating substrates 85 and 87 are formed of a material whose main component is alumina.

The control device 3 includes a microcomputer (hereinafter sometimes referred to as "microcomputer") 91, an application specific integrated circuit (hereinafter sometimes referred to as "ASIC") 93, and a heater voltage supply circuit 95. Equipped with. The microcomputer 91 is a microcomputer chip equipped with a CPU (Central Processing Unit) 91a, a ROM (Read Only Memory) 91b, a RAM (Random Access Memory) 91c, etc. with a known configuration.

The ASIC 93 includes an Ip detection circuit 101, an Ip drive circuit 103, a resistance detection circuit 105, a voltage output circuit 107, a reference voltage comparison circuit 109, an Icp supply circuit 111, and the like.

The Ip detection circuit 101 converts the current Ip flowing between the electrodes 71 and 73 of the Ip cell 67 into a voltage, and outputs the converted voltage to the microcomputer 91 as a detection signal. The resistance detection circuit 105 is a circuit that periodically supplies a current of a predetermined value to the Vs cell 69 and detects the amount of voltage change (amount of change in voltage Vs) obtained in response to the energization. be. A value indicating the amount of change in voltage Vs detected by this resistance detection circuit 105 is output to the microcomputer 91.

The microcomputer 91 determines the impedance of the Vs cell 69 based on the value output from the resistance detection circuit 105 and a table in which the amount of change in the voltage Vs and the impedance Ri of the Vs cell 60 are associated in advance, which is stored in the ROM 91b. Ri is required. The impedance Ri of the Vs cell 69 is correlated with the temperature of the Vs cell 69, that is, the temperature of the entire sensor element 51, and the microcomputer 91 determines the temperature of the gas sensor 2 (sensor element 51) based on the impedance Ri of the Vs cell 69. Detect.

Voltage output circuit 107 detects electromotive force Vs generated between electrodes 79 and 81 of Vs cell 69. The reference voltage comparison circuit 109 compares a predetermined reference voltage with the electromotive force Vs detected by the voltage output circuit 107 and outputs the comparison result to the Ip drive circuit 103. The Ip drive circuit 103 controls the magnitude and direction of the current Ip supplied between the electrodes 71 and 83 of the Ip cell 67 based on the comparison result output from the reference voltage comparison circuit 109. The Icp supply circuit 111 supplies a small current Icp flowing from the electrode 81 of the Vs cell 69 toward the electrode 79.

As described later, the heater voltage supply circuit 95 generates a voltage Vh to be applied to both ends of the heater 83 under known PI control in response to instructions from the CPU 91a (heater control unit 91d) of the microcomputer 91. At the same time, by applying a predetermined voltage (for example, 12 V in the case of a detection mode described later) to both ends of the heater (heating resistor) 83, the heater 83 generates heat.

Here, the basic operation of the gas sensor 2 will be briefly explained. Here, the operation of detecting the oxygen concentration of the detection target gas (air-fuel ratio of exhaust gas) using the gas sensor 2 will be described. Note that when detecting the air-fuel ratio of exhaust gas, a reference voltage (for example, 450 mV) to be compared is set in the reference voltage comparison circuit 109.

First, the Icp supply circuit 111 supplies a minute current Icp from the electrode 81 of the Vs cell 69 to the electrode 79 via the solid electrolyte body 57. By this energization, oxygen in the exhaust gas becomes oxygen ions and moves from the electrode 79 side to the electrode 81 side via the solid electrolyte body 57.

When a minute current Icp is supplied to the Vs cell 69, oxygen ions move from the electrode 79 side to the electrode 81 side, creating an oxygen concentration atmosphere that serves as a reference for generating an electromotive force Vs according to the oxygen concentration in the exhaust gas. generated.

The voltage output circuit 107 detects the electromotive force Vs between the electrodes 79 and 81 and outputs the detected electromotive force Vs to the reference voltage comparison circuit 109. The reference voltage comparison circuit 109 compares the electromotive force Vs and the reference voltage, and outputs the comparison result to the Ip drive circuit 103.

The Ip drive circuit 103 controls the magnitude and direction of the current Ip supplied between the electrodes 71 and 73 of the Ip cell 67, based on the comparison result by the reference voltage comparison circuit 109, so that the electromotive force Vs becomes the reference voltage. do. As a result, oxygen is pumped into or out of the detection chamber 63 by the Ip cell 67.

Here, if the air-fuel ratio of the exhaust gas that has flowed into the detection chamber 63 is richer than the stoichiometric air-fuel ratio, the electrodes 71 and 73 are connected so that oxygen is pumped into the detection chamber 63 from the outside in the Ip cell 67. The magnitude and direction of the supplied current Ip are controlled. On the other hand, when the air-fuel ratio of the exhaust gas flowing into the detection chamber 63 is leaner than the stoichiometric air-fuel ratio, oxygen is supplied between the electrodes 71 and 73 in the Ip cell 67 so as to pump oxygen from the detection chamber 63 to the outside. The magnitude and direction of the current Ip are controlled.

The current Ip at this time is converted into a voltage by the Ip detection circuit 101, and the voltage-converted current Ip is output to the microcomputer 91 as a detection signal. The microcomputer 91 calculates a value corresponding to the oxygen concentration contained in the detection target gas and further the air-fuel ratio of the exhaust gas based on the detection signal. In this way, the oxygen concentration of the detection target gas (the air-fuel ratio of the exhaust gas) is detected using the gas sensor 2.

Next, a method for controlling energization of the heater 83 (a heating control method for the gas sensor control device 1) performed in the gas sensor control device 1 will be described. Note that this energization control of heater 83 is performed while HV vehicle 200 is running.

FIG. 2 is a block diagram showing an example of the functional configuration of the microcomputer 91. As shown in FIG. In the microcomputer 91, a heater control section 91d, a first determination section 91e, a second determination section 91f, a third determination section 91g, a fourth determination section 91h, and a fifth determination section 91i are constructed using software.

Here, the contents of processing executed in the heater control section 91d and the like of the microcomputer 91 will be explained with reference to FIG. FIG. 3 is a flowchart showing processing related to power supply control of the heater 83, which is executed by the microcomputer 91. When the ignition switch is operated and the hybrid system (ECU 207, etc.) of the HV vehicle 200 is started, the ECU 207 executes a process of selecting the motor drive mode as the drive mode. In such a situation, when the user (driver) depresses the accelerator pedal, HV vehicle 200 starts running in the motor drive mode from a stopped state. Thereafter, ECU 207 executes processing to switch the driving mode as appropriate depending on the driving situation (required driving force, etc.) of HV vehicle 200.

While the HV vehicle 200 is running, the first determining unit 91e determines whether the driving mode is the motor driving mode (that is, whether the driving mode is the motor driving mode or the engine driving mode), as shown in step S11. judgment) is executed (first judgment step). Information on the driving mode of the HV vehicle is periodically supplied from the ECU 207 to the microcomputer 91, and the first determination unit 91e can acquire the information on the driving mode as appropriate. In step S11, if the first determination unit 91e determines that the mode is the motor drive mode, the process moves to step S12. On the other hand, if it is determined in step S11 that the mode is not the motor drive mode (that is, the engine drive mode), the process moves to step S21.

In step S21, the heater control unit 91d executes a process of causing the heater 83 to generate heat at an activation temperature (for example, 750° C.) that makes the sensor element (detection cell) 51 in a detectable state. The heater control unit 91d applies a predetermined voltage (heater control voltage 1) to both ends of the heater (heating resistor) 83 via the heater voltage supply circuit 95, aiming at a predetermined activation temperature. Heater control voltage 1 is, for example, 12V. Note that in this specification, the mode in which the heater 83 is energized is referred to as a "heater control mode." A heater control mode in which the heater 83 generates heat at an activation temperature (for example, 750° C.) is referred to as a "detection mode." Further, a heater control mode in which the heater 83 is de-energized to stop the heater 83 from generating heat is referred to as a "stop mode." When the process in step S21 ends, the process returns to step S11 again.

In step S12, the second determination unit 91f executes a process of determining whether the charge level of the battery 204 exceeds the first threshold value α (second determination step). The first threshold value α is a predetermined value and is stored in the ROM 91b. The first threshold value α is set, for example, as a charge level of 50% of the charge level of the battery 204 when the battery 204 is fully charged. In step S12, if the second determination unit 91f determines that the charge level of the battery 204 exceeds the first threshold value α, the process moves to step S13. On the other hand, if it is determined in step S12 that the charge level of the battery 204 does not exceed the first threshold α (that is, if the charge level is determined to be equal to or lower than the first threshold α), the process moves to step S20. .

In step S20, the heater control unit 91d executes a process of causing the heater 83 to generate heat at an activation temperature (for example, 750° C.) that makes the sensor element 51 detectable. The processing content of step S20 is basically the same as step S21 described above. When the process in step S20 ends, the process returns to step S11 again.

In step S13, the third determination unit 91g executes a process of determining whether the heater control mode is the stop mode (third determination step). In step S13, if the third determination unit 91g determines that the mode is the stop mode, the process moves to step S14. On the other hand, if it is determined in step S13 that the heater control mode is not the stop mode, the process moves to step S15.

In step S14, the fourth determination unit 91h executes a process of determining whether the charge level of the battery 204 is below the second threshold value β (fourth determination step). The second threshold value β is a predetermined value, and is set as a value larger than the first threshold value α described above (β>α). If it is determined in step S14 that the charge level of the battery 204 is lower than the second threshold value β, the process moves to step S16. On the other hand, if it is determined in step S14 that the charge level of the battery 204 is not lower than the second threshold β (that is, if the charge level is determined to be equal to or higher than the second threshold β), the process moves to step S17. .

In step S16, the heater control unit 91d controls the energization of the heater 83 in a standby mode in which the heater 83 generates heat at a standby temperature (for example, 550° C.) lower than the activation temperature. The heater control unit 91d applies a predetermined voltage (heater control voltage 2) to both ends of the heater (heating resistor) 83 via the heater voltage supply circuit 95, aiming at a predetermined standby temperature. Heater control voltage 2 is a value lower than heater control voltage 1 described above. In this specification, the heater control mode in which the heater 83 generates heat at a standby temperature lower than the activation temperature is referred to as the "standby mode" as described above. When the process in step S16 ends, the process returns to step S11 again.

In step S17, the heater control unit 91d controls the energization of the heater 83 while maintaining the heater control mode in the stop mode. Therefore, in step S17, the state in which the heat generation of the heater 83 is stopped is maintained. When the process in step S17 is completed, the process returns to step S11 again.

In step S15, the fifth determination unit 91i executes a process of determining whether the charge level of the battery 204 exceeds the third threshold value γ (fifth determination step). The third threshold value γ is a predetermined value, and is set as a value larger than the above-mentioned second threshold value (γ>β). If it is determined in step S15 that the charge level of the battery 204 exceeds the third threshold value γ, the process moves to step S18. On the other hand, if it is determined in step S15 that the charge level of the battery 204 does not exceed the third threshold value γ (that is, if the charge level is determined to be equal to or lower than the third threshold value γ), the process moves to step S19. do.

When the process moves to step S18, the heater control unit 91d controls the energization of the heater 83 in the stop mode. That is, in step S18, the heat generation of the heater 83 is stopped. When the process in step S18 ends, the process returns to step S11 again.

In step S19, the heater control unit 91d controls the energization of the heater 83 in a standby mode in which the heater 83 generates heat at a standby temperature (for example, 550° C.) lower than the activation temperature. When the process in step S19 ends, the process returns to step S11 again.

Note that the heater control section 91d is configured to select and switch the heater control mode according to the charge level of the battery 204.

FIG. 4 is an explanatory diagram showing the relationship between the charge level of the battery 204 and the driving mode and the relationship between the charge level of the battery 204 and the heater control mode in the hybrid vehicle 200. FIG. 4 shows a graph in which the vertical axis corresponds to the charge level of the battery 204 and the horizontal axis corresponds to time. Here, the processing contents executed in the microcomputer 91 (heater control unit 91, etc.) at each timing from time t1 to time t8 shown in the graph of FIG. 4 will be explained with reference to the flowchart of FIG. 3.

At time t1, the driving mode of HV vehicle 200 is motor driving mode, and charge level L1 of battery 204 satisfies β<L1<γ. The energization control of the heater 83 in this case is performed so that the flowchart of FIG. 3 moves in the order of step S11, step S12, step S13, step S14, and step S17. Then, in step S17, the heater control unit 91d controls the energization of the heater 83 while maintaining the heater control mode in the stop mode. In other words, the heat generation of the heater 83 is stopped. As described above, at the timing of time t1, the charge level L1 of the battery 204 is sufficiently high (β<L1), and since it is expected that the vehicle will be driven in the motor drive mode for some time from now, the heater control mode remains in the stop mode. maintained.

At time t2, the driving mode of the HV vehicle 200 is the motor driving mode, and the charge level L2 of the battery 204 is higher than the first threshold α and lower than the second threshold β (that is, α<L2<β ). The energization control of the heater 83 in this case is performed so that the flowchart of FIG. 3 moves in the order of step S11, step S12, step S13, step S14, and step S16. Then, in step S16, the heater control section 91d switches the heater control mode from the stop mode to the standby mode, and controls the energization of the heater 83 in the standby mode. The heater 83 generates heat to a standby temperature (for example, 550° C.). In this way, at time t2, the charge level L2 of the battery 204 falls below the second threshold β, and it is expected that the driving mode will switch to the engine driving mode in the near future, so the heater control mode is switched to the standby mode. It will be done.

At time t3, the driving mode of the HV vehicle 200 is the engine driving mode, and the charge level L3 of the battery 204 is less than the first threshold value α. The energization control of the heater 83 in this case is performed so that the flowchart of FIG. 3 moves in the order of step S11 and step S21. Then, in step S21, the heater control section 91d switches the heater control mode from the standby mode to the detection mode, and controls the energization of the heater 83 in the detection mode. The heater 83 generates heat to reach an activation temperature (for example, 750° C.). As described above, at the timing of time t3, since the driving mode has been switched to the engine driving mode, the heater control mode becomes the detection mode.

At time t4, the driving mode of the HV vehicle 200 is the motor driving mode, and the charge level L4 of the battery 204 exceeds the first threshold α and falls below the third threshold γ (that is, α<L4<γ ). The energization control of the heater 83 in this case is performed so that the flowchart of FIG. 3 moves in the order of step S11, step S12, step 13, step S15, and step S19. Then, in step S19, the heater control section 91d switches the heater control mode from the detection mode to the standby mode, and controls the energization of the heater 83 in the standby mode. The heater 83 generates heat to a standby temperature (for example, 550° C.). As described above, at time t4, the driving mode has been switched from the engine driving mode to the motor driving mode, but since the charge level L4 of the battery 204 is below the third threshold γ, the driving mode will be switched again in the near future. Since there is a possibility of switching to the engine running mode, the heater control mode becomes a standby mode.

At time t5, the driving mode of HV vehicle 200 is motor driving mode, and charge level L5 of battery 204 exceeds third threshold γ (that is, γ<L5). The energization control of the heater 83 in this case is performed so that the flowchart of FIG. 3 moves in the order of step S11, step S12, step 13, step S15, and step S18. Then, in step S18, the heater control section 91d switches the heater control mode from the standby mode to the stop mode, and controls the energization of the heater 83 in the stop mode. In other words, the heat generation of the heater 83 is stopped. As described above, at time t5, the driving mode is the motor driving mode, and the charge level L5 of the battery 204 exceeds the third threshold value and is sufficiently high, so it is expected that the vehicle will be traveling in the motor driving mode for some time from now. Therefore, the heater control mode is switched to the stop mode.

At time t6, the driving mode of the HV vehicle 200 is the motor driving mode, and the charge level L6 of the battery 204 is higher than the second threshold value β and lower than the third threshold value γ (that is, β<L6<γ ). The processing content of the heater control unit 91d in this case is the same as that at time t1.

At time t7, the driving mode of the HV vehicle 200 is the motor driving mode, and the charge level L7 of the battery 204 exceeds the first threshold value α and falls below the second threshold value β (that is, α<L7<β ). The processing content of the heater control unit 91d in this case is the same as that at time t2.

At time t8, although the driving mode of HV vehicle 200 is the motor driving mode, the charge level L8 of battery 204 is equal to or lower than the first threshold value α. The energization control of the heater 83 in this case is performed so that the flowchart of FIG. 3 moves in the order of step S11, step S12, and step S20. Then, in step S20, the heater control section 91d switches the heater control mode from the standby mode to the detection mode, and controls the energization of the heater 83 in the detection mode. In this case, anticipating that the ECU 17 will immediately switch the driving mode from the motor driving mode to the engine driving mode, the heater control section 91d switches the heater control mode to the detection mode, and also controls the energization of the heater 83 in the detection mode. I do.

As described above, in the gas sensor control device 1 of the present embodiment, the heater control unit 91d determines that the first determination unit 91e determines that the mode is motor running mode, and the second determination unit 91f determines that the mode exceeds the first threshold α. In this case, the energization of the heater 83 is controlled in either a standby mode in which the heater 83 generates heat at a standby temperature (e.g., 550° C.) lower than the activation temperature (e.g., 750° C.) or a stop mode in which the energization of the heater 83 is stopped. I do. Therefore, the gas sensor control device 1 can suppress the power consumption of the heater 83 in the motor running mode.

Furthermore, in the gas sensor control device 1 of this embodiment, the heater control unit 91d selects either the standby mode or the stop mode according to the charge level of the battery 204, and controls the energization of the heater 83. Therefore, the gas sensor control device 1 can suppress the power consumption of the heater 83 in the motor drive mode based on the charge level of the battery.

Furthermore, in the gas sensor control device 1 of the present embodiment, when the charge level of the battery 204 falls below the second threshold β (however, β>α) when the heater control unit 91d is in the stop mode, the heater control unit 91d switches to the standby mode. Then, the heater 83 is controlled to be energized. In this way, by knowing the charge level of the battery 204 in the stop mode, it is possible to predict that the driving mode will switch from the motor driving mode to the engine driving mode in the near future. ) 51 can be warmed in advance to a somewhat high standby temperature. Therefore, in the gas sensor control device 1, when the motor drive mode is switched to the engine drive mode in the near future, the sensor element (detection cell) 51 of the gas sensor can be quickly brought into a detectable state. Such a gas sensor control device 1 suppresses the power consumption of the heater 83 of the gas sensor 2 during driving in the motor driving mode, and when the motor driving mode is switched to the engine driving mode, the sensor element (detection cells) 51 are maintained in a rapidly detectable state.

Furthermore, in the gas sensor control device 1 of the present embodiment, when the charge level of the battery 204 exceeds the third threshold γ (however, γ>β) while in the standby mode, the heater control unit 91d switches to the stop mode. Then, the heater 83 is controlled to be energized. As described above, by knowing the charge level of the battery 204 in the standby mode, it is predicted that the vehicle will be running in the motor drive mode for some time, and therefore the heater control mode will be set to the stop mode. Therefore, in the gas sensor control device 1, the power consumption of the heater 83 in the motor running mode can be suppressed.

Furthermore, in the gas sensor control device 1 of the present embodiment, the heater control unit 91d controls the charge level of the battery 204 to a second threshold value β ( , β>α), the detection mode is switched to the standby mode, or the standby mode is maintained, and the energization of the heater 83 is controlled. In this way, by knowing the charge level of the battery 204 in a mode other than the stop mode, it is possible to know that there is a possibility that the driving mode will switch back to the engine driving mode in the near future. The control mode becomes standby mode. Therefore, in the gas sensor control device 1, when the motor drive mode is switched to the engine drive mode in the near future, the sensor element (detection cell) 51 of the gas sensor can be quickly brought into a detectable state. Such a gas sensor control device 1 suppresses the power consumption of the heater 83 of the gas sensor 2 during driving in the motor driving mode, and when the motor driving mode is switched to the engine driving mode, the sensor element (detection cells) 51 are maintained in a rapidly detectable state.

The heating control method for the gas sensor control device 1 includes a first determination step of determining whether the driving mode is an engine driving mode that uses the driving force of the engine 201 or a motor driving mode that uses only the driving force of the motor 202. , a second determination step of determining whether the charge level of the battery 204 exceeds the first threshold α, and the determination result of the first determination step is the motor running mode, and the first threshold α is set in the second determination step. If it is determined that the temperature exceeds the active temperature, the heater control unit 91d controls the energization of the heater 83 in either a standby mode in which the heater 83 generates heat at a standby temperature lower than the activation temperature, or a stop mode in which the energization of the heater 83 is stopped. The energization control step (step S16, step S17, step S18, step S19) is provided.

In the energization control step (step S16, step S17, step S18, step S19), the heater control unit 91d selects either standby mode or stop mode according to the charge level of the battery 204, and energizes the heater 83. Take control.

In the energization control step (step S16), when the charge level of the battery 204 falls below the second threshold value β (however, β>α) in the stop mode, the heater control unit 91d changes the heater control mode to the standby mode. , and controls the energization of the heater 83.

In the energization control step (step S18), when the charge level of the battery 204 exceeds the third threshold value γ (however, γ>β) in the standby mode, the heater control unit 91d changes the heater control mode to the stop mode. , and controls the energization of the heater 83.

In the energization control step (step S19), when the charge level of the battery 204 is equal to or higher than the second threshold value β (however, β>α) when the mode is other than the stop mode (that is, the detection mode or the standby mode). , the heater 83 is controlled to be energized by switching from the detection mode to the standby mode or maintaining the standby mode.

DESCRIPTION OF SYMBOLS 1... Gas sensor control device, 2... Gas sensor, 3... Control device, 51... Sensor element (detection cell), 83... Heater, 91... Microcomputer, 91d... Heater control section, 91e... First determination section, 91f... Second determination Part, 200...Hybrid vehicle, 201...Engine, 202...Motor with power generation function, 204...Battery, 208...Exhaust pipe

Claims (8)

It is attached to the exhaust pipe of the engine in a hybrid vehicle that is equipped with an engine and a motor with a power generation function as a driving force source, and a battery that supplies electric power to the motor or stores electric power from the motor, and detects the concentration of a specific gas. A gas sensor control device that controls a gas sensor having a detection cell that heats the detection cell and a heater that heats the detection cell,
Controlling the energization of the heater and causing the heater to generate heat at an activation temperature that makes the detection cell detectable when the hybrid vehicle is in an engine drive mode that utilizes the driving force of the engine. A gas sensor control device comprising a heater control section,
a first determination unit that determines whether the driving mode is the engine driving mode or a motor driving mode that uses only the driving force of the motor;
a second determination unit that determines whether the charge level of the battery exceeds a first threshold α;
The heater control unit is configured to set the heater to standby at a temperature lower than the activation temperature when the first determination unit determines that the motor running mode is set and the second determination unit determines that the mode exceeds the first threshold α. A gas sensor control device that controls energization of the heater in either a standby mode that generates heat at a temperature or a stop mode that stops energization of the heater. The gas sensor control device according to claim 1, wherein the heater control unit controls energization of the heater by selecting either the standby mode or the stop mode depending on the charge level of the battery. The heater control unit is configured to switch to the standby mode and control energization of the heater when the charge level of the battery falls below a second threshold β (where β>α) when the heater control unit is in the stop mode. The gas sensor control device according to claim 1 or claim 2. The heater control unit is configured to switch to the stop mode and control energization of the heater when the charge level of the battery exceeds a third threshold γ (where γ>β) in the standby mode. The gas sensor control device according to claim 1 or claim 2. It is attached to the exhaust pipe of the engine in a hybrid vehicle that is equipped with an engine and a motor with a power generation function as a driving force source, and a battery that supplies electric power to the motor or stores electric power from the motor, and detects the concentration of a specific gas. a gas sensor having a detection cell that heats the detection cell and a heater that heats the detection cell; and a gas sensor that controls energization of the heater, and when the driving mode of the hybrid vehicle is an engine driving mode that utilizes the driving force of the engine, A heating control method for a gas sensor control device, comprising: a heater control unit that causes the heater to generate heat at an activation temperature that brings the detection cell into a detectable state;
a first determination step of determining whether the driving mode is the engine driving mode or a motor driving mode that uses only the driving force of the motor;
a second determination step of determining whether the charge level of the battery exceeds a first threshold α;
If the determination result of the first determination step is the motor running mode, and the second determination step is determined to exceed the first threshold α, the heater generates heat at a standby temperature lower than the activation temperature. A heating control method comprising: an energization control step in which the heater control section controls energization of the heater in either a standby mode in which the heater is turned off or a stop mode in which energization of the heater is stopped. 6. The heating control according to claim 5, wherein in the energization control step, the heater control section selects either the standby mode or the stop mode to control the energization of the heater, depending on the charge level of the battery. Method. In the energization control step, when the charge level of the battery falls below a second threshold β (where β>α) in the stop mode, the heater control section switches to the standby mode and The heating control method according to claim 5 or 6, wherein energization control of the heater is performed. In the energization control step, when the charge level of the battery exceeds a third threshold γ (where γ>β) in the standby mode, the heater control section switches to the stop mode and turns the heater on. 7. The heating control method according to claim 5 or 6, wherein the energization control is performed.

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