JP2016112910A - Control device for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a hybrid vehicle capable of properly activating a detection element while reducing power consumption and capable of extending the service life of the detection element when activating by a heater, the detection element of a detection device for oxygen concentration during operation stop of an internal combustion engine.SOLUTION: A control device 1 for a hybrid vehicle V comprises an ECU 2. The ECU 2 acquires a charge rate SOC, a catalyst temperature Tcat and an exhaust temperature Tex, and an LAF energization start value SstLAF and an O2 energization start value SstO2 are set to satisfy Sene<SstLAF<Sstp and Sene<SstO2<Sstp in response to the catalyst temperature Tcat and the exhaust temperature Tex when defining a charge start value as Sene and an energization stop value as Sstp. During the operation stop of an internal combustion engine 3, when SOC≥Sstp, energization to heaters 20a and 21a for LAF and O2 is stopped. Besides, when SOC≤SstLAF, energization to the heater 20a for LAF is carried out, and when SOC≤SstO2, the energization to the heater 21a for O2 is carried out (steps 40 to 45, 50 to 54).SELECTED DRAWING: Figure 12

Description

  The present invention relates to a hybrid vehicle control device that controls a heater for heating a detection element of an oxygen concentration detection device in a hybrid vehicle using an internal combustion engine and an electric motor as power sources.

  Conventionally, what was described in patent document 1 as a control apparatus of a hybrid vehicle is known. This hybrid vehicle includes an internal combustion engine and an electric motor as power sources, and an exhaust gas purification catalyst, an O2 sensor, and the like are provided in an exhaust passage of the internal combustion engine. The internal combustion engine is provided with an engine heater for heating the internal combustion engine and a catalyst heater for heating the exhaust gas purification catalyst, and the O2 sensor has an O2 sensor heater for heating the heater. Is built-in.

  In this control device, when the hybrid vehicle is running with only the power of the electric motor in a state where the internal combustion engine is stopped, the preheat control is performed when the state of charge (SOC) of the battery becomes a predetermined value SOC2 or less. The process is executed for a predetermined time. In this preheat control process, the exhaust gas purification catalyst and the O2 sensor are heated by simultaneously turning on the catalyst heater and the O2 sensor heater in order to activate the exhaust gas purification catalyst and the O2 sensor. During the preheat control process, when the charging rate SOC becomes equal to or lower than the predetermined value SOC1 smaller than the predetermined value SOC2, the engine is started to charge the battery (FIG. 2 of the same document). Steps 10 to 18, FIG. 3).

JP 2003-269208 A

  According to the hybrid vehicle control apparatus disclosed in Patent Document 1, the preheat control process is started at the timing when the battery charge rate SOC becomes equal to or lower than the predetermined value SOC2, and the catalyst heater and the O2 sensor heater are simultaneously turned on. . That is, since the heating of the O2 sensor by the O2 sensor heater is executed regardless of the temperature state of the detection element of the O2 sensor, the heating amount of the heater has a value necessary to activate the detection element of the O2 sensor. In such a case, the power consumption may be increased or the detection element of the O2 sensor may be deactivated.

  In the case of the O2 sensor, in order to estimate the active state / inactive state of the detection element, it is common to energize the detection element and measure the impedance thereof. This is executed regardless of the ON / OFF state of the heater. At that time, as described above, when the O2 sensor heater is turned off and the detection element of the O2 sensor is in an inactive state, if the detection element is energized for impedance measurement, the detection element is deteriorated. Will be promoted. As a result, the lifetime of the O2 sensor is shortened, and the O2 sensor needs to be replaced, resulting in an increase in running cost.

  The present invention has been made to solve the above-described problems. When the detection element of the oxygen concentration detection device is activated by a heater while the operation of the internal combustion engine is stopped, the detection element is reduced while reducing power consumption. It is an object of the present invention to provide a control device for a hybrid vehicle that can be appropriately activated and can extend the life of a detection element.

  In order to achieve the above object, the invention according to claim 1 includes an internal combustion engine 3 and an electric motor 4 as power sources, a battery (battery 11) capable of transferring electric power between the electric motor 4, and the internal combustion engine 3. An oxygen concentration detection device (LAF sensor 20, O2 sensor 21) that detects the oxygen concentration in the exhaust gas in the exhaust passage 8 via a detection element, and a heater (LAF heater 20a, O2 heater 21a) for heating the detection element ), The charging rate acquisition means (ECU 2, current voltage sensor 27) for acquiring the charging rate SOC of the battery, and the detection element when the operation of the internal combustion engine 3 is stopped. Temperature parameter acquisition means (ECU2, exhaust temperature sensor 22, step 40) for acquiring temperature parameters (catalyst temperature Tcat, exhaust temperature Tex) representing temperature, and heater ( Heater energization start values (LAF energization start value SstLAF, O2 energization start value SstO2), which are threshold values of the charging rate SOC at which energization to the AF heater 20a and O2 heater 21a) should be started, are obtained temperature parameters. Accordingly, a predetermined charge start point SOC that is greater than a predetermined charge start value Sene, which is a threshold value of the charge rate SOC at which charging of the capacitor is to be started, and is a predetermined threshold value of the charge rate SOC at which energization to the heater is to be stopped. The heater energization start value setting means (ECU2, steps 41, 50) that is set to be smaller than the heater energization stop value SStp and the operation of the internal combustion engine 3 are stopped when the operation of the internal combustion engine 3 is stopped. When the charging rate SOC acquired in the above is equal to or greater than a predetermined heater energization stop value Sstp, the energization to the heater is stopped and the operation of the internal combustion engine 3 Heater control means (ECU2, step 42) for energizing the heater when the charging rate SOC acquired during the stop is equal to or less than the set heater energization start value (LAF energization start value SstLAF, O2 energization start value SstO2). To 45, 51 to 54).

  According to this hybrid vehicle control device, the charging rate of the battery is acquired, the temperature parameter indicating the temperature of the detection element is acquired while the operation of the internal combustion engine is stopped, and the charging rate at which energization to the heater is to be started The heater energization start value that is a threshold value of the battery becomes greater than a predetermined charge start value that is a threshold value of the charging rate at which charging of the battery is to be started according to the acquired temperature parameter, and It is set to be smaller than a predetermined heater energization stop value which is a threshold value of the charging rate at which energization should be stopped. When the operation of the internal combustion engine is stopped, when the charging rate acquired during the operation stop of the internal combustion engine is equal to or greater than a predetermined heater energization stop value, the energization to the heater is stopped, and the internal combustion engine Energization of the heater is executed when the charging rate acquired during the operation stop is equal to or less than the set heater energization start value.

  In other words, when the internal combustion engine is stopped, the charging rate of the capacitor becomes equal to or less than the heater energization start value, so that the charging rate of the capacitor decreases to a predetermined charging start value from the time when energization to the heater is started. The heater is energized until charging is started, that is, until the internal combustion engine is restarted. Thereby, even when the detection element is in an inactive state in the period from when the internal combustion engine is stopped to when the internal combustion engine is restarted, the energization start timing to the heater for activating the detection element However, since it is set according to the detection element temperature, the amount of electric power supplied to the heater for activating the detection element can be set according to the temperature of the detection element. As a result, it is possible to appropriately activate the detection element while reducing power consumption, and to improve the merchantability (in addition, “acquisition of charging rate” and “acquisition of temperature parameter” in this specification) "Acquisition" such as "is not limited to directly detecting / measuring these values by a sensor or the like, but includes estimating / calculating these values using other parameters).

  According to a second aspect of the present invention, in the control device 1 for the hybrid vehicle V according to the first aspect, the impedance acquisition means (LAF impedance Z_LAF, O2 impedance Z_O2) for acquiring the impedance (LAF impedance Z_LAF, O2 impedance Z_O2) of the detection element by energizing the detection element. ECU2, steps 66 and 76) and energization prohibiting means (ECU2, step 63) for prohibiting the impedance acquisition means from energizing the detection element when the operation of the internal combustion engine 3 is stopped and energization to the heater is stopped. The heater energization start value setting means includes temperature parameters (catalyst temperature Tcat, exhaust temperature Tex) acquired when energization to the detection element is prohibited by the energization prohibiting means. ) Heater energization start value (LAF energization start value SstLAF, O2 energization) To set the opening value SstO2) (step 41, 51) that is characterized.

  According to this hybrid vehicle control device, when the operation of the internal combustion engine is stopped and the energization of the heater is stopped, the energization of the detection element is prohibited, and thus the energization of the detection element is prohibited. The heater energization start value is set according to the temperature parameter acquired during the operation. That is, the heater energization start value can be set without performing energization to the detection element for obtaining the impedance. Accordingly, the heater can be energized to activate the detection element while avoiding energization of the detection element in a state where the detection element is inactive, and the life of the oxygen concentration detection device Can be extended. As a result, the running cost can be reduced and the merchantability can be further improved.

  According to a third aspect of the present invention, in the control device 1 for the hybrid vehicle V according to the second aspect, the activity determination means (ECU 2, step 60) for determining whether or not the detection element is in an active state according to the temperature parameter. , 70), and the energization prohibiting means is configured such that when the internal combustion engine 3 is stopped and the energization of the heaters (LAF heater 20a, O2 heater 21a) is performed, the detection element is in an inactive state. When it is determined that there is, it is characterized in that energization of the detection element by the impedance acquisition means is prohibited (steps 63 to 65, 73 to 75).

  According to this hybrid vehicle control device, whether or not the detection element is in an activated state is determined according to the temperature parameter, and the detection is performed when the internal combustion engine is stopped and the heater is energized. When it is determined that the element is in an inactive state, energization of the detection element by the impedance detection unit is prohibited. As a result, even when the heater is being energized, when the detection element is in an inactive state, the energization of the detection element can be prohibited, thereby further avoiding deterioration of the detection element and extending the life of the oxygen concentration detection device. It can be further extended. As a result, the running cost can be further reduced, and the merchantability can be further improved.

  According to a fourth aspect of the present invention, in the control device 1 for the hybrid vehicle V according to any one of the first to third aspects, the heater control means is configured such that the charging rate SOC is a heater energization start value (LAF energization start value SstLAF, O2 energization). In accordance with the temperature parameters (catalyst temperature Tcat, exhaust temperature Tex) acquired at or below the start value SstO2), the energization amount (LAF control input Ulaf, O2 control) to the heater (LAF heater 20a, O2 heater 21a) The input Uo2) is determined (steps 45 and 54).

  According to this hybrid vehicle control device, since the amount of current supplied to the heater is determined according to the temperature parameter acquired when the charging rate is equal to or lower than the heater energization start value, impedance acquisition is performed during energization of the heater. Even when energization of the detection element by the means is prohibited, the energization amount after the start of energization of the heater can be set to an optimum value according to the temperature of the detection element.

It is a figure which shows typically the structure of the control apparatus which concerns on one Embodiment of this invention, and the hybrid vehicle to which this is applied. It is a flowchart which shows an operation mode control process. It is a flowchart which shows a heater control process. It is a flowchart which shows the LAF heater control process at the time of EV. It is a figure which shows an example of the map used for calculation of LAF energization start value SstLAF. It is a figure which shows an example of the map used for calculation of the LAF control input Ulaf. It is a flowchart which shows O2 heater control processing at the time of EV. It is a figure which shows an example of the map used for calculation of O2 energization start value SstO2. It is a figure which shows an example of the map used for calculation of O2 control input Uo2. It is a flowchart which shows the measurement process of LAF impedance Z_LAF. It is a flowchart which shows the measurement process of O2 impedance Z_O2. It is a timing chart which shows an example of a control result.

  Hereinafter, a hybrid vehicle control device according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the control device 1 of the present embodiment controls a hybrid vehicle (hereinafter referred to as “vehicle”) V and includes an ECU 2. The vehicle V includes an internal combustion engine (hereinafter referred to as “engine”) 3 and an electric motor (hereinafter referred to as “motor”) 4 as power sources.

  In this vehicle V, the crankshaft 3a of the internal combustion engine 3 is mechanically coupled to left and right front wheels 7 and 7 as drive wheels via a clutch 5, an automatic transmission 6, and the like. The clutch 5 is of an electromagnetic clutch type and is electrically connected to the ECU 2. In the clutch 5, the engagement / disconnection state is controlled by a control input signal from the ECU 2.

  The automatic transmission 6 is a belt CVT type continuously variable transmission, and includes a CVT actuator (not shown) electrically connected to the ECU 2. In the automatic transmission 6, the gear ratio is controlled by driving the CVT actuator by a control input signal from the ECU 2.

  With the above configuration, the power of the engine 3 and / or the electric motor 4 is transmitted to the front wheels 7 and 7 while being shifted by the automatic transmission 6. On the other hand, when the engine is started, the power of the electric motor 4 is transmitted to the engine 3 side with the clutch 5 engaged. The vehicle V includes left and right rear wheels (not shown) that are idle wheels.

  The engine 3 is a multi-cylinder internal combustion engine using gasoline as fuel, and includes a fuel injection valve 3b and a spark plug 3c (only one is shown) provided for each cylinder. Both the fuel injection valve 3b and the spark plug 3c are electrically connected to the ECU 2. The fuel injection amount of the fuel injection valve 3b is determined by the ECU 2 in accordance with the traveling state of the vehicle V and the operating state of the engine 3. The injection timing and the ignition timing of the air-fuel mixture by the spark plug 3c are controlled.

  On the other hand, an LAF sensor 20, an exhaust gas purification catalyst 9, an O2 sensor 21, and an exhaust temperature sensor 22 are provided in the exhaust passage 8 of the engine 3 in order from the upstream side. The LAF sensor 20 is composed of zirconia and a platinum electrode, and the oxygen concentration in the exhaust gas flowing in the exhaust passage 8 is measured in a wide range of air-fuel ratios from a rich region richer than the stoichiometric air-fuel ratio to an extremely lean region. It detects linearly and outputs a detection signal representing it to the ECU 2. The ECU 2 executes air-fuel ratio control based on detection signals from the LAF sensor 20 and the O2 sensor 21.

  The LAF sensor 20 has a built-in LAF heater 20a. The LAF heater 20a is for heating and activating a detection element (not shown) of the LAF sensor 20. The LAF heater 20a is electrically connected to the ECU 2. The ECU 2 controls the ON / OFF state and the heat generation amount as will be described later.

  Further, the O2 sensor 21 is composed of zirconia and a platinum electrode, and outputs a detection signal based on the oxygen concentration in the exhaust gas that has passed through the exhaust gas purification catalyst 9 to the ECU 2. The O2 sensor 21 incorporates an O2 heater 21a, and the O2 heater 21a is for heating and activating a detection element (not shown) of the O2 sensor 21. The O2 heater 21a is electrically connected to the ECU 2, and as will be described later, the ON / OFF state and the heat generation amount are controlled by the ECU 2. In the present embodiment, the LAF sensor 20 and the O2 sensor 21 correspond to an oxygen concentration detection device, and the LAF heater 20a and the O2 heater 21a correspond to a heater.

  The exhaust gas purification catalyst 9 is of a three-way catalyst type, and purifies unburned fuel and the like in the exhaust gas flowing through the exhaust passage 8. Further, the exhaust temperature sensor 22 detects the temperature of the exhaust gas flowing in the exhaust passage 8 (hereinafter referred to as “exhaust temperature”) Tex, and outputs a detection signal representing it to the ECU 2. In this case, the exhaust temperature Tex has a very high correlation with the temperature of the detection element of the O2 sensor 21 and corresponds to a value representing the detection element temperature of the O2 sensor 21. In the present embodiment, the exhaust temperature sensor 22 corresponds to a temperature parameter acquisition unit, and the exhaust temperature Tex corresponds to a temperature parameter.

  On the other hand, the motor 4 is configured by a brushless DC motor, and is electrically connected to the ECU 2 and the battery 11 (capacitor) via the PDU 10. The PDU 10 is composed of an electric circuit including an inverter. The ECU 2 controls transmission / reception of electric power between the motor 4 and the battery 11 via the PDU 10, thereby controlling the torque generated by the motor 4 during acceleration traveling of the vehicle V and the like. During deceleration traveling, etc., power regeneration by the motor 4 is controlled.

  In addition, a generator 12 is electrically connected to the battery 11. The generator 12 is driven by the power of the engine 3 and is electrically connected to the ECU 2. During operation of the engine 3, the ECU 2 controls charging of the battery 11 by the generator 12.

  Further, the ECU 2 is electrically connected to a crank angle sensor 23, a motor speed sensor 24, an accelerator opening sensor 25, four wheel speed sensors 26 (only one shown), a current voltage sensor 27, and a brake switch 28. Has been. The crank angle sensor 23 includes a magnet rotor and an MRE pickup, and outputs a CRK signal, which is a pulse signal, to the ECU 2 as the crankshaft 3a rotates. The CRK signal is output at one pulse every predetermined crank angle (for example, 2 °), and the ECU 2 calculates the engine speed NE (hereinafter referred to as “engine speed”) NE based on the CRK signal.

  The motor rotation number sensor 24 outputs a detection signal, which is a pulse signal corresponding to the rotation of the motor 4, to the ECU 2. The ECU 2 calculates the rotational speed (hereinafter referred to as “motor rotational speed”) NMOT of the motor 4 based on the detection signal of the motor rotational speed sensor 24. Further, the accelerator opening sensor 25 detects an accelerator opening AP, which is an operation amount of an accelerator pedal (not shown), and outputs a detection signal representing it to the ECU 2.

  On the other hand, the four wheel speed sensors 26 output detection signals representing the rotational speeds of the left and right front wheels 7 and 7 and the left and right rear wheels to the ECU 2, respectively. The ECU 2 calculates the vehicle speed VP based on the detection signals of these wheel speed sensors 26. Further, the current / voltage sensor 27 (charging rate acquisition means) outputs a detection signal representing the current / voltage value input / output to / from the battery 11 to the ECU 2. The ECU 2 calculates the charging rate SOC (%) of the battery 11 based on the detection signal of the current / voltage sensor 27.

  Furthermore, the brake switch 28 is provided in a brake pedal mechanism (not shown), and outputs an output signal to the ECU 2 in accordance with the depression state of the brake pedal. Specifically, the brake switch 28 outputs an ON signal when the brake pedal is depressed by a predetermined amount or more, and outputs an OFF signal at other times.

  On the other hand, the ECU 2 includes a microcomputer including a CPU, a RAM, a ROM, an I / O interface (all not shown), and the detection signals of the various sensors 20 to 27 and the brake switch 28 described above. As described below, various control processes such as an operation mode control process and a heater control process are executed in accordance with the output signal.

  In the present embodiment, the ECU 2 corresponds to a charging rate acquisition unit, a temperature parameter acquisition unit, a heater energization start value setting unit, a heater control unit, an impedance acquisition unit, an energization prohibition unit, and an activity determination unit.

  Next, the operation mode control process will be described with reference to FIG. As will be described below, this operation mode control process executes the EV mode and the ENG mode as the operation mode, and is executed by the ECU 2 at a predetermined control cycle. The EV mode is an operation mode in which the power running control process and the regenerative control process of the motor 4 are executed in a state where the operation of the engine 3 is stopped. The ENG mode is irrespective of whether the motor 4 is operated or stopped. This is an operation mode in which the engine 3 is operated.

  As shown in the figure, first, in step 1 (abbreviated as “S1” in the figure, the same applies hereinafter), a condition determination process is executed. In this condition determination process, the EV execution condition flag F_EV_CND is used to determine which execution condition of the EV mode or ENG mode is satisfied as the operation mode executed in the current operation mode control process, and to indicate the determination result. The value of is set.

  Although the contents of this condition determination processing are not shown, specifically, based on various parameters such as the vehicle speed VP, the accelerator opening AP, the charging rate SOC, and the engine speed NE, and the output signal of the brake switch 28, the EV When the execution condition of the mode is satisfied, the EV execution condition flag F_EV_CND is set to “1” to indicate that, and when the execution condition of the ENG mode is satisfied, the EV execution is performed. The condition flag F_EV_CND is set to “0”. In particular, when the charging rate SOC becomes equal to or lower than a predetermined charging start value Sene, the EV execution condition flag F_EV_CND is set to “0” in order to operate the engine 3 and execute power generation by the generator 12.

  In step 1, after performing the condition determination process as described above, the process proceeds to step 2 to determine whether or not the EV execution condition flag F_EV_CND is “1”. If the determination result is YES and the execution condition of the EV mode is satisfied, the process proceeds to step 3 to determine whether or not the previous value F_EVz of the EV mode flag is “1”.

  If the determination result is YES and the ENG mode is being executed at the previous control timing, the routine proceeds to step 4 where it is determined whether or not the engine speed NE is equal to or less than a predetermined speed NE1. When the determination result is YES, it is determined that the EV mode should be executed, and in order to represent it, the process proceeds to step 5 and the EV mode flag F_EV is set to “1”.

  On the other hand, when the determination result in step 4 is NO, it is determined that the ENG mode should be executed, and in order to represent it, the process proceeds to step 8 and the EV mode flag F_EV is set to “0”.

  In addition, when the determination result of step 3 described above is NO and the EV mode is being executed at the previous control timing, it is determined that the EV mode should be continuously executed, Proceeding to step 5 described above, the EV mode flag F_EV is set to “1”.

  On the other hand, if the determination result of step 2 is NO and the execution condition of the ENG mode is satisfied, the process proceeds to step 6 to determine whether or not the previous value F_EVz of the EV mode flag is “1”. If the determination result is YES and the EV mode is being executed at the previous control timing, the process proceeds to step 7 to determine whether or not to start engine start by the motor 4 (hereinafter referred to as “motor start”).

  When this determination result is YES and the motor start is started, it is determined that the EV mode should be stopped and the ENG mode should be started, and in order to represent it, the process proceeds to the above-described step 8, and the EV mode flag F_EV Is set to “0”.

  On the other hand, when the determination result in step 7 is NO, it is determined that the EV mode should be continuously executed because the motor start is not started although the execution condition of the ENG mode is satisfied. In order to represent this, the process proceeds to step 5 described above, and the EV mode flag F_EV is set to “1”.

  On the other hand, when the determination result of step 6 is NO and the ENG mode is being executed at the previous control timing, it is determined that the ENG mode should be continuously executed, and in order to express it, the above-mentioned is described. Proceeding to step 8, the EV mode flag F_EV is set to “0”.

  In Step 9 following Step 5 or 8 described above, it is determined whether or not the EV mode flag F_EV is “1”. When the determination result is YES, the process proceeds to step 10 to execute the EV mode control process. In this EV mode control process, the power running control process and the regenerative control process of the motor 4 are performed based on various parameters such as the vehicle speed VP, the accelerator opening AP, the charging rate SOC, the engine speed NE, and the output signal of the brake switch 28. Etc. are executed.

  In step 10, after executing the EV mode control process as described above, the present process is terminated.

  On the other hand, when the determination result of step 9 is NO, the process proceeds to step 11 to execute the ENG mode control process. In this ENG mode control process, the generated torque of the engine 3 is controlled based on various parameters such as the vehicle speed VP, the accelerator pedal opening AP, the charging rate SOC, the engine speed NE, and the output signal of the brake switch 28. In addition, when the assist control execution condition is satisfied, the assist control process by the motor 4 is executed. That is, the power running control process of the motor 4 is executed in order to assist the torque required for the vehicle V with the torque generated by the motor 4 in addition to the torque generated by the engine 3.

  In step 11, after performing the ENG mode control process as described above, the present process is terminated.

  Next, the heater control process will be described with reference to FIG. This heater control process controls the energization state of the LAF heater 20a and the O2 heater 21a described above, and is executed at a predetermined control cycle.

  As shown in the figure, first, in step 20, it is determined whether or not the EV mode flag F_EV described above is “1”. If the determination result is YES and the EV mode is being executed, the process proceeds to step 21 to determine whether or not the previous value F_EVz of the EV mode flag is “0”.

  When the determination result is YES and the current control timing is the timing when the ENG mode is switched to the EV mode, the process proceeds to step 22 to determine whether or not the charging rate SOC is equal to or higher than a predetermined heater energization stop value Sstp. To do. The predetermined heater energization stop value Sstp is a constant value set so that Sstp> Sene is satisfied.

  When the determination result is YES, it is determined that the heater control process for the EV mode should be executed, and to represent it, the process proceeds to step 23, and the EV heater control flag F_EV_HT is set to “1”. .

  On the other hand, when the determination result in step 22 is NO, it is determined that the heater control process for normal time should be executed, and in order to represent it, the process proceeds to step 24, and the EV heater control flag F_EV_HT is set to “0”. To "".

  On the other hand, if the determination result in step 21 is NO and the EV mode is being executed at the previous control timing, the process proceeds to step 25 described below.

  In step 25 following the above steps 21, 23, or 24, it is determined whether or not the EV heater control flag F_EV_HT is “1”. When the determination result is YES, the process proceeds to step 26, and the EV time LAF heater control process is executed as the EV mode control process of the LAF heater 20a.

  Specifically, this EV LAF heater control process is executed as shown in FIG. As shown in the figure, first, in step 40, a calculation process of the catalyst temperature Tcat which is the temperature of the exhaust gas purification catalyst 9 is executed. In this calculation process, although not shown, for example, the catalyst temperature Tcat (temperature parameter) is calculated by the calculation method proposed by the present applicant in Japanese Patent Laid-Open No. 2001-173504. That is, the catalyst temperature Tcat is calculated according to parameters such as the engine speed NE, the pressure in the intake passage, the atmospheric pressure, and the intake air temperature. In this case, the catalyst temperature Tcat has a very high correlation with the temperature of the detection element of the LAF sensor 20, and corresponds to a value representing the detection element temperature of the LAF sensor 20.

  Next, the routine proceeds to step 41, where a LAF energization start value SstLAF (heater energization start value) is calculated by searching the map shown in FIG. 5 according to the catalyst temperature Tcat. The LAF energization start value SstLAF is a threshold value of the charging rate SOC of the battery 11 for determining whether or not energization to the LAF heater 20a is started. As shown in FIG. The higher the value is, the smaller the value is set. This is because the higher the catalyst temperature Tcat, the higher the temperature of the detection element of the LAF sensor 20 is estimated, and accordingly, the stop time of the LAF heater 20a is set longer. In the case of this map, the LAF energization start value SstLAF is set so that Sene <SstLAF <Sstp is satisfied.

  Next, in step 42, it is determined whether or not the charging rate SOC is larger than the LAF energization start value SstLAF. When the determination result is YES, the energization to the LAF heater 20a is stopped, it is determined that the LAF heater 20a should be turned off, and the process proceeds to step 43, where the energization to the LAF heater 20a is stopped.

  Next, the process proceeds to step 44, where the LAF heater stop flag F_LAF_OFF is set to “1” in order to indicate that energization to the LAF heater 20a is stopped, and then the present process ends.

  On the other hand, when the determination result in step 42 is NO and SOC ≦ SstLAF is established, the LAF heater 20a is energized to heat the LAF sensor 20 by the LAF heater 20a, and the LAF heater 20a is energized. It is determined that the heater 20a should be turned on, the process proceeds to step 45, and the EV energization control process is executed.

  In this EV energization control process, the LAF control input Ulaf is calculated by searching the map shown in FIG. 6 according to the catalyst temperature Tcat, and the control input signal corresponding to the LAF control input Ulaf is the LAF heater 20a. To be supplied. The LAF control input Ulaf (energization amount to the heater) is calculated as a duty ratio, and is set to a larger value as the catalyst temperature Tcat is lower, as shown in FIG. This is because the lower the catalyst temperature Tcat is, the lower the temperature of the detection element of the LAF sensor 20 is, so that the amount of heat generated by the LAF heater 20a is set larger.

  Next, the process proceeds to step 46, in which the LAF heater stop flag F_LAF_OFF is set to “0” to indicate that the energization of the LAF heater 20a is being executed, and then the present process is terminated.

  Returning to FIG. 3, after executing the EV LAF heater control process in step 26 as described above, the process proceeds to step 27, and the EV O2 heater control process is executed as the EV mode control process of the O2 heater 21 a. To do.

  Specifically, the EV O2 heater control process is executed as shown in FIG. As shown in the figure, first, in step 50, an O2 energization start value SstO2 (heater energization start value) is calculated by searching the map shown in FIG. 8 according to the exhaust temperature Tex.

  The O2 energization start value SstO2 is a threshold value of the charge rate SOC of the battery 11 for determining whether or not energization to the O2 heater 21a is started. As shown in FIG. The higher the value is, the smaller the value is set. This is because the higher the exhaust gas temperature Tex, the higher the temperature of the detection element of the O2 sensor 21, and accordingly, the stop time of the O2 heater 21 a is set longer. In the case of this map, the O2 energization start value SstO2 is set so that Sene <SstO2 <Sstp is satisfied.

  Next, in step 51, it is determined whether or not the charging rate SOC is larger than the O2 energization start value SstO2. When the determination result is YES, the energization to the O2 heater 21a is stopped, it is determined that the O2 heater 21a should be turned off, the process proceeds to step 52, and the energization to the O2 heater 21a is stopped.

  Next, the routine proceeds to step 53, where the O2 heater stop flag F_O2_OFF is set to “1” in order to indicate that the energization to the O2 heater 21a is stopped, and then this processing is terminated.

  On the other hand, if the determination result in step 51 is NO and SOC ≦ SstO2 is satisfied, it is determined that the O2 heater 21a should be energized and the O2 heater 21a should be turned on. Then, the EV energization control process is executed.

  In the EV energization control process, an O2 control input Uo2 is calculated by searching the map shown in FIG. 9 according to the exhaust gas temperature Tex, and a control input signal corresponding to the O2 control input Uo2 is the O2 heater 21a. To be supplied. The O2 control input Uo2 (energization amount to the heater) is calculated as a duty ratio, and is set to a larger value as the exhaust gas temperature Tex is lower as shown in FIG. This is because the lower the exhaust gas temperature Tex, the lower the temperature of the detection element of the O2 sensor 20 is estimated, and accordingly, the amount of heat generated by the O2 heater 21a is set to be larger.

  Next, the process proceeds to step 55, where the O2 heater stop flag F_O2_OFF is set to “0” in order to indicate that the energization of the O2 heater 21a is being performed, and then this process is terminated.

  Returning to FIG. 3, in step 27, the heater control process for O2 during EV is executed as described above, and the heater control process in FIG.

  On the other hand, when the determination result in step 25 described above is NO, that is, the EV mode is being executed, but the charging rate SOC is lower than the predetermined heater energization stop value SStp, the normal heater control process (hereinafter referred to as the heater control process) Steps 30 and 31) are determined to be executed, and the process proceeds to step 30 to execute the normal LAF heater control process.

  In this normal time LAF heater control process, the catalyst temperature Tcat is calculated by the above-described method, and the LAF control input Ulaf is calculated by searching the above-described map of FIG. 6 according to the catalyst temperature Tcat. A control input signal corresponding to the LAF control input Ulaf is supplied to the LAF heater 20a.

  Next, the routine proceeds to step 31 where normal O2 heater control processing is executed. In this normal O2 heater control process, the O2 control input Uo2 is calculated by searching the map shown in FIG. 9 according to the exhaust gas temperature Tex, and a control input signal corresponding to the O2 control input Uo2 is O2. Supplied to the heater 21a.

  As described above, after executing the normal O2 heater control process in step 31, the present process is terminated.

  On the other hand, if the determination result in step 20 is NO and the ENG mode is being executed, the process proceeds to step 28 to determine whether or not the previous value F_EVz of the EV mode flag is “1”.

  When the determination result is YES and the current control timing is the timing when the EV mode is switched to the ENG mode, it is determined that the normal heater control process should be executed, and this is expressed by In step 29, the EV heater control flag F_EV_HT is set to “0”, and then, as described above, steps 30 and 31 are executed, and this process is terminated.

  On the other hand, if the determination result in step 28 is NO and the ENG mode is being executed at the previous control timing, as described above, after executing steps 30 and 31, this process is terminated.

  Next, the LAF_Z measurement process will be described with reference to FIG. This process measures the impedance (hereinafter referred to as “LAF impedance”) Z_LAF of the detection element of the LAF sensor 20 and is executed by the ECU 2 at a predetermined control cycle.

  As shown in the figure, first, in step 60, LAF activity determination processing is executed. In this LAF activity determination process, when the catalyst temperature Tcat is equal to or higher than a predetermined activation temperature, it is determined that the detection element of the LAF sensor 20 is in an active state, and the LAF activation flag F_LAF_ACT is set to “1”. Sometimes, it is determined that the detection element of the LAF sensor 20 is in an inactive state, and the LAF activation flag F_LAF_ACT is set to “0”.

  In step 61 following step 60, it is determined whether or not the EV heater control flag F_EV_HT is "1". If the determination result is YES and the EV heater control is being executed, the routine proceeds to step 62, where it is determined whether or not the engine speed NE is 0.

  When the determination result is YES and the engine 3 is stopped, the process proceeds to step 63 to determine whether or not the LAF heater stop flag F_LAF_OFF is “1”. If the determination result is YES and the energization to the LAF heater 20a is stopped, it is determined that the energization to the detection element of the LAF sensor 20 should be stopped and the impedance measurement should be stopped, and step 64 is performed. Then, after stopping the measurement of the LAF impedance Z_LAF, the present process is terminated.

  On the other hand, if the determination result in step 63 is NO and energization of the LAF heater 20a is being executed, the process proceeds to step 65, where it is determined whether or not the LAF activation flag F_LAF_ACT is “1”. If the determination result is YES and the detection element of the LAF sensor 20 is in an inactive state, as described above, measurement of the LAF impedance Z_LAF is stopped in step 64, and then this process is terminated.

  On the other hand, when the determination result of step 61, 62 or 65 is NO, that is, when the normal heater control process is executed, the engine 3 is in operation, or the detection element of the LAF sensor 20 is activated. When it is in the state, it is determined that the detection element of the LAF sensor 20 should be energized and the impedance measurement should be executed, and the process proceeds to step 66, where the measurement current is passed through the detection element of the LAF sensor 20 and the LAF impedance Z_LAF After the measurement, this process is terminated.

  Next, the O2_Z measurement process will be described with reference to FIG. This process is to measure the impedance (hereinafter referred to as “O2 impedance”) Z_O2 of the detection element of the O2 sensor 21, and is executed by the ECU 2 at a predetermined control cycle.

  As shown in the figure, first, in step 70, O2 activity determination processing is executed. In this O2 activation determination process, when the exhaust gas temperature Tex is equal to or higher than a predetermined activation temperature, it is determined that the detection element of the O2 sensor 21 is in an active state, and the O2 activation flag F_O2_ACT is set to “1”. Otherwise, it is determined that the detection element of the O2 sensor 21 is in an inactive state, and the O2 activation flag F_O2_ACT is set to “0”.

  In step 71 following step 70, it is determined whether or not the EV heater control flag F_EV_HT is “1”. If the result of this determination is YES and the EV heater control process is being executed, the routine proceeds to step 72 where it is determined whether or not the engine speed NE is 0.

  When the determination result is YES and the engine 3 is stopped, the process proceeds to step 73 to determine whether or not the O2 heater stop flag F_O2_OFF is “1”. If the determination result is YES and energization of the O2 heater 20a is stopped, it is determined that the energization of the detection element of the O2 sensor 21 should be stopped and the impedance measurement should be stopped, and step 74 is performed. Then, the process of O2 impedance Z_O2 is stopped, and the process is terminated.

  On the other hand, if the determination result in step 73 is NO and the energization of the O2 heater 20a is being executed, the process proceeds to step 75 to determine whether or not the O2 activation flag F_O2_ACT is “1”. If the determination result is YES and the detection element of the O2 sensor 21 is in an inactive state, as described above, in step 74, the measurement of the O2 impedance Z_O2 is stopped, and then this process is terminated.

  On the other hand, when the determination result in the above steps 71, 72 or 75 is NO, that is, when the normal heater control process is executed, the engine 3 is in operation, or the detection element of the O2 sensor 21 is activated. When the current is in the state, it is determined that the detection element of the O2 sensor 21 should be energized and the impedance measurement should be performed, and the process proceeds to step 76, where the measurement current is passed through the detection element of the O2 sensor 21, After measuring the impedance Z_O2, the present process is terminated.

  Next, an example of a control result when the above various control processes are executed (hereinafter referred to as “control result example”) will be described with reference to FIG. In the example of the control result shown in the figure, in the heater control process of FIG. 3 described above, at the EV mode execution start timing, the charging rate SOC ≧ Sstp is established, and the EV heater control process (steps 26 and 27) is executed. The control result on the LAF sensor 20 side at that time is mainly shown.

  Further, in the data curve of the LAF impedance Z_LAF in the figure, the data indicated by a solid line is an actual measurement value, and the data indicated by a broken line is an estimate of the impedance transition during measurement stop. Further, a value Z_LAF1 in the figure is a predetermined threshold value that satisfies Z_LAF ≦ Z_LAF1 when the LAF sensor 20 is in an active state.

  As shown in FIG. 12, when the EV mode execution condition is satisfied at time t1, the EV execution condition flag F_EV_CND is set to “1”. Thereafter, as the engine speed NE decreases, the EV mode flag F_EV is set to “1” at the timing (time t2) when NE ≦ NE1 is satisfied.

  At this timing, when the charging rate SOC ≧ Sstp is satisfied, the EV heater control flag F_EV_HT is set to “1”, and the EV LAF heater control process is executed. At this timing, when the charging rate SOC> SstLAF is satisfied, the energization of the LAF heater 20a is stopped and the LAF heater stop flag F_LAF_OFF is set to “1” in the EVA LAF heater control process.

  As time elapses, at time t3, the engine 3 is stopped, and when NE = 0 is established, the measurement of the LAF impedance Z_LAF is stopped thereafter. Furthermore, the LAF activation flag F_LAF_ACT is set to “0” at the timing (time t4) when the catalyst temperature Tcat falls below a predetermined activation temperature as the engine 3 is stopped.

  Thereafter, energization of the LAF heater 20a is started at the timing (time t5) when the charging rate SOC ≦ SstLAF is satisfied as time elapses. Thereafter, as the detection element of the O2 sensor 21 is heated, the impedance measurement is stopped, but the LAF impedance Z_LAF decreases.

  Next, when the charging rate SOC ≦ Sene is satisfied at time t6, the EV execution condition flag F_EV_CND is set to “0”. The LAF activation flag F_LAF_ACT is set to “1” at the timing (time t7) when the catalyst temperature Tcat becomes equal to or higher than the predetermined activation temperature due to the energization of the LAF heater 20a. Thereafter, the LAF impedance Z_LAF Measurement is performed.

  Next, when engine start by the motor 4 is started at time t8, the EV mode flag F_EV is set to “0”, and at the same time, the EV heater control flag F_EV_HT is set to “0”. As a result, the ENG mode is started, the engine 3 is started by the motor 4, and after the start of the engine 3, the motor 4 is stopped and the engine 3 is operated to charge the battery 11 by the generator 12. Is executed, and the charging rate SOC increases.

  As described above, according to the control device 1 of the present embodiment, during the EV mode, when the charge rate SOC is equal to or higher than the predetermined heater energization stop value Sstp, the EV-time LAF is performed as the heater control process for the EV mode. Heater control processing and EV O2 heater control processing are executed. In this EV time LAF heater control process, while energization of the LAF heater 20a is stopped, the LAF energization start value SstLAF is calculated according to the catalyst temperature Tcat, and when SOC> SstLAF is satisfied, the LAF heater 20a Energization of the LAF heater 20a is executed when SOC ≦ SstLAF is satisfied. That is, even when the detection element of the LAF sensor 20 is in an inactive state during execution of the EV mode, the energization start timing to the LAF heater 20a for activating the detection element is the catalyst temperature Tcat. Therefore, the amount of electric power supplied to the LAF heater 20a can be set according to the temperature of the detection element without excess or deficiency. As a result, it is possible to appropriately activate the detection element of the LAF sensor 20 while reducing the power consumption, and to improve the merchantability.

  Further, since the LAF energization start value SstLAF is calculated while the impedance measurement of the detection element is stopped while the energization to the LAF heater 20a is stopped, the energization to the detection element for impedance measurement is not performed. The start timing of energization to the LAF heater 20a can be determined. As a result, energization of the LAF heater 20a can be started in order to activate the detection element while avoiding energization of the detection element when the detection element is in an inactive state. Can be extended. For the same reason, even when energization to the detection element for impedance measurement is prohibited while energization to the LAF heater 20a is stopped, the energization start timing to the LAF heater 20a depends on the temperature of the detection element. By being able to set appropriately, the energization amount after energization start can be set to the optimal value according to element temperature.

  Even after the start of energization to the LAF heater 20a, when the detection element of the LAF sensor 20 is in an inactive state, the energization to the detection element for impedance acquisition is stopped. Even when energization is performed, when the detection element is in an inactive state, energization of the detection element of the LAF sensor 20 is prohibited, so that deterioration of the detection element can be further avoided and the life of the LAF sensor 20 can be further extended. . As a result, the running cost can be further reduced, and the merchantability can be further improved.

  On the other hand, in the EV O2 heater control process, the O2 energization start value SstO2 is calculated according to the exhaust gas temperature Tex while energization of the O2 heater 21a is stopped, and when SOC> SstO2 is satisfied, the O2 heater When energization to 21a is stopped and SOC ≦ SstO2 is satisfied, energization to the O2 heater 21a is performed. That is, even when the detection element of the O2 sensor 20 is in an inactive state during execution of the EV mode, the start timing of energization to the O2 heater 21a for activating the detection element is the exhaust temperature Tex. Accordingly, the amount of power supplied to the O2 heater 21a can be set according to the temperature of the detection element without excess or deficiency. As a result, it is possible to appropriately activate the detection element of the O2 sensor 20 while reducing the amount of power consumption, and to improve the merchantability.

  Further, since the O2 energization start value SstO2 is calculated while the impedance measurement of the detection element is stopped while the energization to the O2 heater 21a is stopped, the energization to the detection element for impedance measurement is not performed. The start timing of energization to the O2 heater 21a can be determined. As a result, energization of the O2 heater 21a can be started in order to activate the detection element while avoiding energization of the detection element when the detection element is in an inactive state, and the life of the O2 sensor 20 can be started. Can be extended. For the same reason, even when energization to the detection element for impedance measurement is prohibited while energization to the O2 heater 21a is stopped, the start timing of energization to the O2 heater 21a is determined according to the temperature of the detection element. By being able to set appropriately, the energization amount after energization start can be set to the optimal value according to element temperature.

  Even after the start of energization of the O2 heater 21a, when the detection element of the O2 sensor 20 is in an inactive state, the energization of the detection element for impedance acquisition is stopped. Even during energization, when the detection element is in an inactive state, energization of the detection element of the O2 sensor 20 is prohibited, so that deterioration of the detection element can be further avoided and the life of the O2 sensor 20 can be further extended. . As a result, the running cost can be further reduced, and the merchantability can be further improved.

  In the embodiment, the hybrid vehicle of the present invention is not limited to the series system, the parallel system, and the split system, and may be any vehicle that includes an internal combustion engine and an electric motor as a power source.

  In addition, the embodiment is an example in which a battery is used as a capacitor, but the capacitor of the present invention is not limited to this, and may be any device that can exchange power with an electric motor. For example, a capacitor may be used as the capacitor.

  Further, the embodiment is an example in which the LAF sensor 20 and the O2 sensor 21 are used as the oxygen concentration detection device, but the oxygen concentration detection device of the present invention is not limited to these, and detects the oxygen concentration in the exhaust gas in the exhaust passage. Any device may be used as long as it can be detected via the element.

  On the other hand, the embodiment is an example in which the current voltage sensor 27 is used as the charging rate acquisition unit. However, the charging rate acquisition unit of the present invention is not limited to this, and may be any unit that acquires the charging rate of the battery. For example, an electric circuit may be used as the charging rate acquisition unit.

  The embodiment is an example in which the catalyst temperature Tcat and the exhaust temperature Tex are used as temperature parameters. However, the temperature parameter of the present invention is not limited to these, and may represent the temperature of the detection element of the oxygen concentration detection device. That's fine. For example, the temperature of the detection element itself of the oxygen concentration detection device may be directly detected by a sensor, and the detected temperature of the detection element itself may be used as a temperature parameter.

  Furthermore, although the embodiment is an example in which the catalyst temperature Tcat is estimated, the catalyst temperature Tcat may be directly detected by a temperature sensor. The embodiment is an example in which the exhaust gas temperature Tex is detected by the exhaust gas temperature sensor 22, but the exhaust gas temperature Tex may be estimated by a method similar to the method for estimating the catalyst temperature Tcat.

  On the other hand, the embodiment is an example in which constant values are used as the predetermined charging start value Sene and the predetermined heater energization stop value Sstp, and these values Sene and Sstp are used as the outside temperature during the control process. You may calculate by the map search method according to various parameters.

V hybrid vehicle 1 control device 2 ECU (charging rate acquisition means, temperature parameter acquisition means, heater energization start value setting means, heater control means, impedance acquisition means, energization prohibition means, activity determination means)
3 Internal combustion engine 4 Electric motor 8 Exhaust passage 11 Battery (capacitor)
20 LAF sensor (oxygen concentration detector)
20a LAF heater 20a (heater)
21 O2 sensor (oxygen concentration detector)
21a O2 heater 21a (heater)
22 Exhaust temperature sensor (temperature parameter acquisition means)
27 Current-voltage sensor (charging rate acquisition means)
Tcat catalyst temperature (temperature parameter)
Tex exhaust temperature (temperature parameter)
SOC Charging rate Sstp Predetermined heater energization stop value Sene Predetermined charging start value SstLAF LAF energization start value (heater energization start value)
SstO2 O2 energization start value (heater energization start value)
Z_LAF LAF impedance (impedance of detection element)
Z_O2 O2 impedance (impedance of detection element)
Ulaf LAF control input (energization amount to heater)
Uo2 O2 control input (energization amount to heater)

Claims (4)

An internal combustion engine and an electric motor as a power source, a capacitor capable of transferring electric power between the electric motor, an oxygen concentration detection device for detecting an oxygen concentration in exhaust gas in an exhaust passage of the internal combustion engine via a detection element, A control device for a hybrid vehicle including a heater for heating the detection element,
Charging rate acquisition means for acquiring the charging rate of the battery;
Temperature parameter acquisition means for acquiring a temperature parameter indicating the temperature of the detection element during the stop of the operation of the internal combustion engine;
A heater energization start value, which is a threshold value of the charging rate at which energization of the heater is to be started, is set to a threshold value of the charging rate at which charging of the capacitor is to be started according to the acquired temperature parameter. And a heater energization start value setting means for setting the energization start value to be smaller than a predetermined heater energization stop value which is a threshold value of the charging rate at which energization to the heater should be stopped. When,
When the operation of the internal combustion engine is stopped, when the charging rate acquired during the operation stop of the internal combustion engine is equal to or greater than the predetermined heater energization stop value, the energization to the heater is stopped, Heater control means for energizing the heater when the charging rate acquired during the shutdown of the internal combustion engine is less than or equal to the set heater energization start value;
A control apparatus for a hybrid vehicle, comprising: Impedance acquisition means for acquiring the impedance of the detection element by energizing the detection element;
Energization prohibiting means for prohibiting energization of the detection element by the impedance acquisition means when operation of the internal combustion engine is stopped and energization of the heater is stopped;
Further comprising
The heater energization start value setting means sets the heater energization start value according to the temperature parameter acquired when energization to the detection element is prohibited by the energization prohibiting means. The hybrid vehicle control device according to claim 1. Further comprising activity determining means for determining whether or not the detection element is in an active state according to the temperature parameter;
The energization prohibiting means detects the detection by the impedance acquisition means when it is determined that the detection element is in an inactive state when the operation of the internal combustion engine is stopped and energization of the heater is performed. The hybrid vehicle control device according to claim 2, wherein energization of the element is prohibited.   The said heater control means determines the energization amount to the said heater according to the said temperature parameter acquired when the said charging rate is below the said heater energization start value, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. A control apparatus for a hybrid vehicle according to claim 1.

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