JP2004232647A - Heater control device for air-fuel ratio sensor for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure favorable startability of an internal combustion engine by controlling energization quantity in preheating in accordance with power consumption of a starter as well as a state of a battery. <P>SOLUTION: This heater control device controls energization to a heater for an air-fuel ratio sensor provided in the internal combustion engine. It is provided with a preheating means to energize the heater before start of the internal combustion engine, a starter power predicting means to predict power consumption of the starter when the internal combustion engine is started, and an energization control means to control an energization state to the heater by the preheating means based on the predicted power consumption. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a heater control device for an air-fuel ratio sensor for an internal combustion engine, and more particularly to a heater control device for an air-fuel ratio sensor having a function of heating the air-fuel ratio sensor before starting the internal combustion engine.

  In the internal combustion engine, air-fuel ratio feedback control for controlling the air-fuel ratio toward the stoichiometric air-fuel ratio is performed by correcting the fuel injection amount based on the air-fuel ratio of the exhaust passage. According to the air-fuel ratio feedback control, it is possible to obtain an effect that the purification performance of the exhaust gas by the catalytic converter is maintained at a high level and the fuel efficiency is prevented from deteriorating. In order to realize such air-fuel ratio feedback control, an air-fuel ratio sensor for detecting the air-fuel ratio is provided in the exhaust passage. Generally, the air-fuel ratio sensor has a characteristic of outputting a signal corresponding to the oxygen concentration in an activated state heated to an activation temperature of several hundred degrees or more. For this reason, the air-fuel ratio sensor has a built-in heater for heating the sensor element to the activation temperature. After energization of the heater of the air-fuel ratio sensor is started, a certain period of time is required until the sensor temperature reaches the activation temperature, that is, until the air-fuel ratio feedback control based on the output signal of the air-fuel ratio sensor becomes possible. Needed. Therefore, conventionally, preheating for starting energization of the heater before the start of the engine has been performed so that the air-fuel ratio feedback control can be started immediately after the start of the internal combustion engine.

  For example, in the air-fuel ratio control device disclosed in Japanese Patent Application Laid-Open No. 5-202785, when the opening of the vehicle door is detected, the start of the internal combustion engine is predicted, and the preheating of the heater of the air-fuel ratio sensor is started. When the sensor temperature reaches a predetermined target temperature, the power supply to the heater is stopped.

  By the way, even when the door open is detected, the internal combustion engine is not always started. In some cases, it is not desirable to perform preheating for some reason, such as when the battery charge is insufficient. However, in the above-described conventional air-fuel ratio control device, when a door open is detected, preheating is always performed, so that the battery may be unnecessarily discharged.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a heater control device for an air-fuel ratio sensor for an internal combustion engine, which can avoid the above problems.

According to one aspect of the present invention, there is provided a heater control device that controls energization of a heater included in an air-fuel ratio sensor provided in an internal combustion engine,
Preheating means for energizing the heater before starting the internal combustion engine,
Battery state detection means for detecting the state of the battery;
Power supply control means for controlling a power supply state to the heater by the preheating means based on a state of the battery;
A heater control device for an air-fuel ratio sensor for an internal combustion engine, comprising:

  In this aspect, the energization control unit controls the energization state of the heater by the preheating unit based on the state of the battery. That is, since the state of the battery is reflected in the state of energization of the heater by the preheating means, the battery is prevented from being excessively discharged during the preheating.

  In this case, the power supply control means may change a power supply time to the heater by the preheating means based on a state of the battery.

Further, a starter power consumption predicting unit for predicting the power consumption of the starter when the internal combustion engine is started,
The power supply control means may control a power supply state of the heater by the preheating means based on the predicted power consumption and a state of the battery. In this case, the energization control unit controls the energization state of the heater by the preheating unit based on the predicted power consumption of the starter and the state of the battery. That is, since both the power consumption of the starter and the state of the battery are reflected in the energization state of the heater by the preheating means, the starter can reliably start the internal combustion engine.

According to another aspect of the present invention,
A heater control device that controls energization of a heater included in an air-fuel ratio sensor provided in an internal combustion engine,
Preheating means for energizing the heater before starting the internal combustion engine,
Starter power prediction means for predicting the power consumption of the starter at the time of starting the internal combustion engine,
Based on the predicted power consumption, an energization control unit that controls an energization state to the heater by the preheating unit,
A heater control device for an air-fuel ratio sensor for an internal combustion engine, comprising:

  In this aspect, the power supply control means controls the power supply state of the heater by the preheating means based on the predicted power consumption of the starter. That is, the power consumption of the starter is reflected in the energization state of the heater by the preheating means, so that the battery is prevented from being excessively discharged during the preheating, thereby ensuring the startability of the internal combustion engine.

  In this case, the power supply control means may prohibit or stop the power supply to the heater by the preheating means when the predicted power consumption exceeds a predetermined value.

  Further, the power supply control means may reduce the amount of power supply to the heater by the preheating means when the predicted power consumption exceeds a predetermined value, as compared with a case where the predicted power consumption does not exceed the predetermined value.

According to another aspect of the present invention, there is provided a heater control device that controls energization of a heater included in an air-fuel ratio sensor provided in an internal combustion engine,
Preheating means for energizing the heater before starting the internal combustion engine,
Preheating unnecessary state detecting means for detecting a predetermined state in which energization of the heater by the preheating means is undesirable,
When the predetermined state is detected, a preheating prohibiting unit that prohibits the heater from being energized by the preheating unit,
A heater control device for an air-fuel ratio sensor for an internal combustion engine, comprising:

  In the present aspect, the preheating prohibiting unit prohibits the preheating in a predetermined state in which the execution of the preheating is not desirable. Therefore, according to the present invention, it is possible to prevent the preheating from being performed unnecessarily, thereby suppressing the discharge of the battery.

  In this case, the predetermined state may be a state in which an abnormality has occurred in the air-fuel ratio sensor.

Further, the internal combustion engine is mounted on a vehicle including a security system that operates when an intruder in the vehicle is detected,
The predetermined state may be a state in which the security system is operating.

According to another aspect of the present invention, there is provided a heater control device that controls energization of a heater included in an air-fuel ratio sensor provided in an internal combustion engine,
Preheating means for energizing the heater before starting the internal combustion engine,
Remote start means for instructing start of the internal combustion engine by remote control;
When the starting operation is performed by the remote start unit, the preheating unit supplies power to the heater with a smaller amount of power than a normal amount of power, and then starts the internal combustion engine during remote operation. Means,
A heater control device for an air-fuel ratio sensor for an internal combustion engine, comprising:

  In this aspect, when the remote start means instructs the start of the internal combustion engine by remote control, it is considered that the vehicle starts running after a certain time has elapsed after the start of the internal combustion engine. For this reason, during the period after the start of the internal combustion engine and before the start of traveling, a temperature rise due to self-heating of the air-fuel ratio sensor can be expected, and the amount of temperature rise of the air-fuel ratio sensor due to preheating is small. Therefore, according to the present invention, when the start operation by the remote operation means is performed, the starting means at the time of the remote operation performs the energization to the heater by the preheating means with a smaller energization amount than the normal energization amount. After that, by starting the internal combustion engine, the power consumption in the preheating is reduced, thereby suppressing the discharge of the battery.

  ADVANTAGE OF THE INVENTION According to this invention, the excessive discharge of a battery by preheating can be prevented by controlling the electricity supply amount in preheating according to the state of a battery.

FIG. 1 is a system configuration diagram of an internal combustion engine to which a heater control device for an air-fuel ratio sensor according to an embodiment of the present invention is applied. The internal combustion engine of the present embodiment is controlled by an electronic control unit (hereinafter, referred to as ECU) 10. As shown in FIG. 1, the internal combustion engine includes a cylinder block 12. Inside the cylinder block 12, a cylinder 14 and a water jacket 16 are formed. The water jacket 16 is provided with a water temperature sensor 18. The water temperature sensor 18 outputs a signal corresponding to the temperature of the cooling water flowing inside the water jacket 16 (hereinafter, referred to as water temperature THW) to the ECU 10. The ECU 10 detects the water temperature THW based on the output signal of the water temperature sensor 18.

  A piston 20 is provided inside the cylinder 14. The piston 20 can slide vertically inside the cylinder 14 in FIG. A cylinder head 22 is fixed to an upper part of the cylinder block 12. An intake port 24 and an exhaust port 26 are formed in the cylinder head 22.

  The bottom surface of the cylinder head 22, the top surface of the piston 20, and the side wall of the cylinder 14 define a combustion chamber. The above-described intake port 24 and exhaust port 26 both open to the combustion chamber 28. The tip of the ignition plug 30 is exposed in the combustion chamber 28. The ignition plug 30 ignites fuel in the combustion chamber 28 by receiving an ignition signal from the ECU 10.

  The internal combustion engine also includes an intake valve 34 and an exhaust valve 36. At the opening of the intake port 24 and the exhaust port 26 to the combustion chamber 28, valve seats for the intake valve 34 and the exhaust valve 36 are formed, respectively. The intake valve 34 and the exhaust valve 36 open and close the intake port 24 and the exhaust port 26, respectively, by being separated from and seated on each valve seat.

  An intake manifold 38 communicates with the intake port 24. The intake manifold 38 is provided with a fuel injection valve 40. The fuel injection valve 40 injects fuel into the intake manifold 38 according to a command signal given from the ECU 10.

  A surge tank 42 communicates with the upstream side of the intake manifold 38. An intake pipe 44 communicates further upstream of the surge tank 42. The intake pipe 44 is provided with a throttle valve 46. An air cleaner 52 communicates upstream of the intake pipe 44. The outside air filtered by the air cleaner 52 flows into the intake pipe 44.

  On the other hand, an exhaust passage 54 communicates with the exhaust port 26 of the internal combustion engine. A catalytic converter 56 is provided in the exhaust passage 54. The catalytic converter 56 purifies the exhaust gas by reacting hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxide (NOX) contained in the exhaust gas. Air-fuel ratio sensors 58 and 60 are disposed upstream and downstream of the catalytic converter 56, respectively. The air-fuel ratio sensors 58 and 60 have the same configuration, and these configurations will be described later. Note that the configurations of the air-fuel ratio sensors 58 and 60 may be different.

  The internal combustion engine includes a rotation speed sensor 62. The rotation speed sensor 62 outputs a pulse signal to the ECU 10 every time the internal combustion engine rotates by a predetermined crank angle. The ECU 10 detects a rotation speed of the internal combustion engine (hereinafter, referred to as an engine rotation speed NE) based on an output signal of the rotation speed sensor 62. Further, the internal combustion engine includes a starter 64. The starter 64 realizes the cranking start of the internal combustion engine by being supplied with the ON signal from the ECU 10.

  FIG. 2 shows an internal configuration of the air-fuel ratio sensors 58 and 60 together with a connection circuit with the ECU 10. As shown in FIG. 2, the air-fuel ratio sensors 58 and 60 include a sensor element 66 made of a material such as zirconia and a heater 68 for heating the sensor element 66 therein.

  One terminal of the sensor element 66 is connected to the constant voltage source 70, and the other terminal is connected to the ECU 10 and grounded via the resistor 72. In the state where the constant voltage is applied to the sensor element 66 in this manner, the current flowing through the sensor element 66 (hereinafter, referred to as sensor current I) is determined by the temperature of the sensor element 66 (hereinafter, referred to as sensor temperature T). When the temperature is equal to or higher than the activation temperature Te (for example, 650 ° C. to 700 ° C.), the temperature varies according to the oxygen concentration in the exhaust passage 54. A voltage corresponding to the sensor current I is input to the ECU 10.

  On the other hand, the heater 68 is connected to the ECU 10 via the power supply control circuit 74. The energization control circuit 74 performs duty control of the energization current to the heater 68 using the battery 75 as a power supply in accordance with a control signal supplied from the ECU 10. A heater voltage detection circuit 76 and a heater current detection circuit 78 are connected to the heater 68. The heater voltage detection circuit 76 outputs a signal corresponding to the voltage applied to the heater 68 to the ECU 10. The heater current detection circuit 78 outputs a signal corresponding to the current flowing through the heater 68 to the ECU 10. The ECU 10 detects a resistance value of the heater 68 (hereinafter, referred to as a heater resistance R) based on these signals.

  A door lock switch 80, a fuel lid switch 82, and an engine hood switch 84 are connected to the ECU 10. The door lock switch 80 is a switch that is turned on only when the vehicle door is unlocked. The fuel lid switch 82 and the engine hood switch 84 are switches that are turned on only when the fuel lid and the engine hood of the vehicle are open. The ECU 10 is further connected to a vehicle speed switch 86. The vehicle speed switch 86 outputs a signal corresponding to the vehicle speed to the ECU 10.

  The ECU 10 controls the amount of power supplied to the heater 68 such that the temperature of the sensor temperature T is equal to or higher than the activation temperature Te and does not damage the sensor element 66 during operation of the internal combustion engine. . Note that the heater resistance R changes according to the temperature of the heater 68. Therefore, the ECU 10 detects the temperature of the heater 68 based on the heater resistance R, and uses this temperature as the sensor temperature T.

  As described above, when the sensor temperature T is maintained at the activation temperature Te or higher, the current flowing through the sensor element 66 changes according to the oxygen concentration. Therefore, the ECU 10 can detect the oxygen concentration in the exhaust passage 54, that is, the air-fuel ratio, based on the sensor current I, by controlling the amount of electricity supplied to the heater 68 as described above. Then, the ECU 10 executes air-fuel ratio feedback control for performing feedback control of the fuel injection amount based on the air-fuel ratio.

  In the air-fuel ratio feedback control, when the air-fuel ratio is richer than the stoichiometric air-fuel ratio, the fuel injection amount is reduced, and when the air-fuel ratio is leaner, the fuel injection amount is increased. It is maintained within a predetermined range near the fuel ratio. The above-described catalytic converter 56 exhibits high purification performance when the air-fuel ratio is near the stoichiometric air-fuel ratio. Therefore, according to the air-fuel ratio feedback control, HC, CO, and NOx in the exhaust gas can be effectively removed by the catalytic converter 56. Further, according to the air-fuel ratio feedback control, the air-fuel ratio does not become excessively rich or lean, so that it is possible to prevent both deterioration of the fuel efficiency and instability of the combustion state.

  During a cold start of the internal combustion engine, the sensor temperature T has almost dropped to the outside air temperature, so that it takes some time before the sensor temperature T is heated to the activation temperature Te. Therefore, in order to start the execution of the air-fuel ratio feedback immediately after the start of the internal combustion engine, for example, when the unlock operation of the vehicle door is detected, the start of the internal combustion engine is predicted, and the air-fuel ratio sensors 58, 60 It is considered that energization of the heater 68 is started. Hereinafter, energization of the heater 68 performed before the engine is started is referred to as preheating of the air-fuel ratio sensors 58 and 60. When the air-fuel ratio sensors 58 and 60 are configured differently, for example, when only the air-fuel ratio sensor 58 is configured to have the heater 68, preheating is performed only on the air-fuel ratio sensor 58.

  However, even when the door is unlocked, the internal combustion engine is not always started. Therefore, if the air-fuel ratio sensors 58 and 60 are always preheated when the opening of the door is detected, the battery 75 is unnecessarily discharged when the internal combustion engine is not started.

  On the other hand, the system of the present embodiment stops the preheating when the driver determines that the driver does not intend to start the internal combustion engine after the preheating is started, so that the battery 75 becomes unnecessary. It is characterized in that discharge can be prevented. Hereinafter, the details of the specific processing executed by the ECU 10 in the present embodiment will be described.

  FIG. 3 is a flowchart of a routine executed by the ECU 10 to start preheating of the air-fuel ratio sensors 58 and 60. FIG. 4 is a flowchart of a routine executed by the ECU 10 to stop preheating when it is determined that the driver has no intention to start the internal combustion engine. The routine shown in FIGS. 3 and 4 and the routine executed in each of the embodiments described below are regular interruption routines that are started at predetermined time intervals before the internal combustion engine is started.

  First, the routine shown in FIG. 3 will be described. When the routine shown in FIG. 3 is started, the process of step 100 is executed.

  In step 100, it is determined whether or not the door has changed from the locked state to the unlocked state. As a result, if a positive determination is made, it is determined that the door has been unlocked, and the process of step 102 is performed next. On the other hand, if a negative determination is made in step 100, the current routine is terminated without any further processing. In step 100, instead of detecting unlocking of the door, it may be detected that the door has been opened.

  In step 102, the preheat permission flag F1 is set to "1". It is assumed that the preheat permission flag F1 has been initialized to “0”. As described later, when the preheat permission flag F1 is set to “1”, the execution of the preheat is permitted. Therefore, according to the processing of steps 100 and 102, the preheating is started when the door is unlocked. When the processing of step 102 ends, the current routine ends.

  Next, the routine shown in FIG. 4 will be described. When the routine shown in FIG. 4 is started, the process of step 104 is executed.

  In step 104, it is determined whether or not the preheat permission flag F1 is set to "1". As a result, if F1 = 1 is not satisfied, then the process of step 105 is executed. On the other hand, if F1 = 1 is satisfied in step 104, the process of step 106 is executed next.

  In step 105, the power supply to the heater 68 is stopped by setting the duty ratio HTduty in the power supply control to the heater 68 to “0”. When the process of step 105 ends, the current routine ends.

  In step 106, the sensor temperature T is detected, and in subsequent step 108, it is determined whether or not the sensor temperature T is higher than the target temperature Tc. Note that the target temperature Tc is set to a temperature higher than the activation temperature Te of the sensor element 66 and not to cause damage to the sensor element 66. If T> Tc is satisfied in step 106, then, in step 110, the duty ratio HTduty is reduced by α, so that the amount of power to the heater 68 is reduced, and then the current routine is terminated. . On the other hand, if T> Tc is not satisfied in step 108, the duty ratio HTduty is increased by α in step 112, so that the amount of power to the heater 68 is increased. . According to the processing of steps 108, 110, and 112, the sensor temperature T is controlled toward the target temperature Tc. The change width α of the duty ratio HTduty may be variable according to the magnitude of the difference between the sensor temperature T and the target temperature Tc.

  Next, the routine shown in FIG. 5 will be described. When the routine shown in FIG. 5 is started, the processing of step 150 is executed.

  In step 150, it is determined whether the preheat permission flag F1 is set to "1". As a result, if F1 = 1 is not satisfied, it is determined that preheating is not being performed, and the current routine is ended. On the other hand, when F1 = 1 is satisfied in step 150, the process of step 152 is executed next.

  In step 152, it is detected whether or not the engine hood is open. As a result, if the engine hood is open, it is determined that the engine room is under inspection. In this case, it is determined that the driver has no intention to start the internal combustion engine, and then in step 154, the preheating is stopped by resetting the preheating permission flag F1 to “0”. When the process of step 154 ends, the current routine ends. On the other hand, if it is determined in step 152 that the engine hood has not been opened, the process of step 156 is executed next.

  In step 156, it is determined whether or not the fuel lid is open. As a result, if the fuel lid is open, it is determined that refueling is in progress. In this case, it is determined that the driver has no intention to start the internal combustion engine, and the pre-heating is stopped by executing the processing of step 154, and then the current routine is ended. On the other hand, if it is determined in step 156 that the fuel lid has not been opened, the process of step 158 is executed next.

  In step 158, it is determined whether the vehicle speed V is equal to or higher than a predetermined value V0. As a result, when V> V0 holds, it is determined that the vehicle is moving while the engine is stopped, that is, it is moving by hand. In this case, it is determined that the driver has no intention to start the internal combustion engine, and the pre-heating is stopped by executing the processing of step 154, and then the current routine is ended. On the other hand, if V> V0 is not satisfied in step 158, the process of step 160 is executed next.

  In step 160, it is determined whether a predetermined time has elapsed while the door open state is maintained. As a result, when an affirmative determination is made, it is determined that inspection and cleaning of the inside of the vehicle is being performed. In this case, it is determined that the driver has no intention to start the internal combustion engine, and the pre-heating is stopped by executing the processing of step 154, and then the current routine is ended. On the other hand, if a negative determination is made in step 160, it is determined that it is not necessary to stop the preheating, and the current routine ends.

  As described above, according to the routine shown in FIG. 3, the start of the internal combustion engine is predicted when the unlock operation of the door is detected, and the preheating is started. On the other hand, in the routine shown in FIG. 4, after the preheating is started, if it is determined that the driver does not intend to start the internal combustion engine, the preheating is stopped. Therefore, according to the present embodiment, when the driver has no intention to start the internal combustion engine, the preheating is not continued, so that unnecessary discharge of the battery 75 is prevented. That is, according to the present embodiment, the preheating is performed only when the probability that the internal combustion engine is started is high, so that the air-fuel ratio sensors 58 and 60 are activated immediately after the engine is started to start the air-fuel ratio feedback control. And discharge of the battery 75 can be suppressed to a necessary minimum.

  Further, in this embodiment, since the discharge of the battery 75 is suppressed, the life of the battery 75 can be extended, and the load on the alternator for charging the battery 75 can be reduced, thereby improving the fuel efficiency. Can be planned. Further, since the battery capacity can be reduced, the cost of the system can be reduced.

  In the above-described embodiment, during the inspection of the engine room, during refueling, during manual pushing, and in the case of inspection and cleaning of the vehicle interior, it is determined that the driver has no intention to start. The situations that can be determined are not limited to these. For example, if the internal combustion engine is not started for a certain period of time after the door is closed and the car radio is turned on, it is determined that the driver is not willing to start because it is waiting for a passenger. You may. In addition, the movement of the driver is detected by a seating sensor or the like provided in the driver's seat, and when the movement of the driver is not detected, it is determined that the driver has not stepped in or is in a waiting state for a fellow passenger. It may be determined that the person has no intention to start.

  Further, in the above-described embodiment, the preheating is stopped when it is determined that the driver has no intention to start the internal combustion engine.However, the present invention is not limited to this. Alternatively, for example, the amount of power supplied during preheating may be reduced by lowering the target temperature Tc.

  Next, a second embodiment of the present invention will be described.

  As described above, the power supply to the heater 68 is performed using the battery 75 as the power supply. Therefore, when the preheating is performed, the battery 75 is discharged, and the charged amount gradually decreases. On the other hand, when starting the cranking of the internal combustion engine, it is necessary to supply a large amount of power from the battery 75 to the starter 64. In the system of this embodiment, even if the door unlock operation is detected, if the capacity of the battery 75 is not sufficient, the execution of the preheating is inhibited, thereby suppressing the discharge of the battery 75 and ensuring the internal combustion engine. The feature is that starting can be guaranteed.

  FIG. 6 is a connection diagram of various sensors and the like to the ECU 10 in the present embodiment. As shown in FIG. 6, the system of the present embodiment has a configuration in which an intake air temperature sensor 88 and a battery / battery specific gravity sensor 90 are further provided in the hardware configuration of the first embodiment.

  The intake air temperature sensor 88 is disposed in the intake pipe 44, and outputs a signal corresponding to the intake air temperature THA to the ECU 10. The battery specific gravity sensor 90 is provided in the battery 75 and outputs a signal corresponding to the specific gravity of the battery liquid (hereinafter, referred to as battery specific gravity BS) to the ECU 10. The ECU 10 detects the intake air temperature THA and the battery specific gravity BS based on the output signals of these sensors. In the present embodiment, the ECU 10 includes a timer CT that counts an elapsed time after the internal combustion engine is stopped (hereinafter, referred to as an elapsed time after stop Ta). The post-stop elapsed time Ta is detected based on the value of this timer.

  When the internal combustion engine is in a low temperature state, the friction increases due to the high viscosity of the lubricating oil, and the power to be supplied to the starter 64 to start the internal combustion engine increases. Therefore, in this case, if sufficient power is not stored in the battery 75 at the time of starting the engine, the power that can be supplied to the starter 64 is insufficient, and the engine startability is deteriorated.

  FIG. 7 shows the relationship between the battery specific gravity BS at the time when the door unlock operation is detected and the time required for starting the internal combustion engine (hereinafter, referred to as starting time Te) when the internal combustion engine is in a low temperature state. Is schematically shown. In FIG. 7, the relationship when the internal combustion engine is started after the preheating is executed is indicated by a solid line, and the relationship when the internal combustion engine is started without the preheating being executed is indicated by a broken line. .

  As shown in FIG. 7, as the battery specific gravity BS increases (that is, as the charge capacity of the battery 75 increases), the power that can be supplied to the starter 64 decreases, so that the start time Te increases. Also, comparing the case where preheating is performed (solid line) and the case where preheating is not performed (dashed line), when preheating is performed, the power that can be supplied to the starter 64 is reduced by the amount of power consumed by preheating. , The start time Te becomes longer. If the start time Te is lengthened, the emission in the exhaust gas is increased due to the deterioration of the startability. Further, if the start time Te exceeds a certain value, the engine starts due to the adhesion of fuel to the ignition plug 30. It will be impossible.

  Therefore, in this embodiment, when the internal combustion engine is in a low temperature state, the ECU 10 determines that the power consumption of the starter 64 at the time of starting the engine is large. Then, in this case, if the battery specific gravity BS is smaller than the predetermined reference value BS0, it is determined that performing the preheating deteriorates the engine startability or the starting becomes impossible, and the preheating is prohibited.

  In the present embodiment, the ECU 10 executes the routine shown in FIG. 8 together with the routine shown in FIG. Hereinafter, the routine shown in FIG. 8 will be described. When the routine shown in FIG. 8 is started, the process of step 200 is executed.

  In step 200, it is determined whether the door has changed from the locked state to the unlocked state (that is, whether or not the door has been unlocked). As a result, if the unlock operation is not detected, the current routine ends. On the other hand, when the unlock operation is detected in step 200, the process of step 201 is executed next.

  In step 201, it is determined whether or not the water temperature THW is lower than a predetermined reference value THW0. As a result, if THW <THW0 is satisfied, the process of step 202 is executed next.

  In step 202, it is determined whether the intake air temperature THA is less than a predetermined reference value THA0. As a result, if THA <THA0 holds, the process of step 204 is executed next.

  In step 204, it is determined whether the post-stop elapsed time Ta exceeds a predetermined reference value Ta0. As a result, when Ta> Ta0 is satisfied, it is determined that the internal combustion engine is sufficiently cooled based on the lapse of time after the internal combustion engine is stopped. In this case, it is determined that the engine is in a low temperature state, that is, the power consumption of starter 64 at the time of starting the engine is large. In this case, the process of step 206 is executed next.

  In step 206, it is determined whether or not the battery specific gravity BS is less than the reference value BS0. As a result, if BS <BS0 holds, then in step 208, the preheating is prohibited by resetting the preheating permission flag F1 to “0”, and then the current routine is ended.

  On the other hand, if a negative determination is made in any of steps 201 to 206, then in step 210, the preheating is permitted by setting the preheating permission flag F1 to "1", and then the current routine ends. Is done.

  As described above, according to the routine shown in FIG. 8, (1) the water temperature THW is lower than the reference value THW0, (2) the intake air temperature THA is lower than the reference value THA0, and (3) the elapsed time Ta after stop is predetermined. Is smaller than the reference value, it is determined that the internal combustion engine is in a low temperature state and the power consumption of the starter 64 is large. Further, (4) when the battery specific gravity BS is smaller than the reference value BS0, it is determined that the charging capacity of the battery 75 is insufficient for realizing good engine startability, and the execution of preheating is prohibited. You. As described above, in the present embodiment, the possibility of preheating is determined in consideration of the magnitude of power consumption of the starter 64 at the time of starting the engine, so that the capacity of the battery 75 has a margin while preventing the deterioration of the engine startability. In some cases, the air-fuel ratio sensors 58 and 60 can be quickly activated after the engine is started by preheating.

  Further, similarly to the case of the first embodiment, since the discharge of the battery 75 can be suppressed, the cost can be reduced by reducing the capacity of the battery 75, the life of the battery 75 can be increased, and the fuel efficiency can be improved by reducing the load on the alternator. Can be planned.

  In the second embodiment, the preheating is prohibited when all of the above (1) to (4) are satisfied. For example, in the extremely low temperature state, the preheating is prohibited among (1) to (4). If any one of the conditions is satisfied, a start failure may occur. Therefore, in such a case, if any one of the conditions (1) to (4) is satisfied, the preheating may be prohibited. In this case, the preheating is more easily prohibited than in the second embodiment. Therefore, the preheating is excessively prohibited by setting each of the reference values THW0, THA0, Ta0, and BS0 to a value smaller than that in the second embodiment. May be prevented.

  In the second embodiment, the preheating is prohibited when the conditions (1) to (4) are satisfied. However, the present invention is not limited to this, and the conditions (1) to (4) are satisfied. In order to reduce the amount of electricity in preheating, the target temperature Tc may be lowered.

  Next, a third embodiment of the present invention will be described.

  In the system of the present embodiment, in the hardware configuration shown in FIGS. 1, 2 and 6 of the second embodiment, even if the unlock operation of the door is detected, the driver has no intention to start the engine. When the determination is made, the feature is that unnecessary power consumption can be prevented by prohibiting preheating.

  In this embodiment, the ECU 10 executes the routine shown in FIGS. 9 and 10 together with the routine shown in FIG. 3 or FIG. First, the routine shown in FIG. 9 will be described. When the routine shown in FIG. 9 is started, the process of step 300 is executed.

  In step 300, it is determined whether or not the engine hood is open. As a result, if the engine hood is open, it is determined that the engine room is under inspection and the driver has no intention to start the internal combustion engine. In this case, after the second permission flag F2 is reset to “0” in step 302, the current routine ends. On the other hand, if the engine hood is closed in step 300, the process of step 304 is executed next.

  In step 304, it is determined whether or not the fuel lid is open. As a result, if the fuel lid is open, it is determined that refueling is in progress and the driver has no intention to start the internal combustion engine. In this case, after the second permission flag F2 is reset to “0”, the current routine ends. On the other hand, if the fuel lid is closed in step 304, then in step 306, the second permission flag F2 is set to "1", and then the current routine ends.

  Next, the routine shown in FIG. 10 will be described. Note that, in the routine shown in FIG. 10, steps that execute the same processing as in the routine shown in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. In the routine shown in FIG. 8, when the preheat permission flag F1 is set to "1" in step 104, the process of step 350 is executed next.

  In step 350, it is determined whether the second permission flag F2 is set to "1". As a result, if F2 = 1 is satisfied, the processing for performing the preheating is performed in step 106 and thereafter, and then the current routine is ended. On the other hand, if F2 = 1 is not satisfied in step 350, the preheat is prohibited in step 114 by setting the duty ratio HTduty to "0", and then the current routine ends.

  As described above, in the present embodiment, the preheating is performed only when the door unlock operation is detected (F1 = 1) and it is determined that the driver has the intention to start the internal combustion engine (F2 = 1). Be executed. For this reason, when the driver has no intention to start, preheating is not performed, so that it is possible to prevent the power of the battery 75 from being unnecessarily consumed. Therefore, according to the present embodiment, the discharge of the battery 75 is suppressed while the air-fuel ratio sensors 58 and 60 are quickly activated after the engine is started by the preheating, so that the cost due to the small capacity of the battery 75 is reduced. It is possible to improve fuel efficiency by down time, prolonging the life of the battery 75, and reducing the load on the alternator.

  In the third embodiment, the preheating is prohibited when it is determined that the engine room is being inspected or the fuel is being refueled. However, similar to the first embodiment, the preheating is prohibited or the passenger is moving. Even when it is determined that the vehicle is waiting, the preheating may be prohibited by determining that there is no intention to start the internal combustion engine.

  Further, in the third embodiment, the preheat is prohibited when it is determined that the driver has no intention to start the internal combustion engine. However, the present invention is not limited to this. For example, the amount of energization in preheating may be reduced by, for example, lowering the target temperature Tc.

  Next, a fourth embodiment of the present invention will be described. The system according to the present embodiment is mounted on a vehicle provided with a security system. In the hardware configuration shown in FIGS. 1, 2, and 6 of the second embodiment, the ECU 10 further includes a security system. It is realized by connecting.

  As described above, the preheating is a process for energizing the heater 68 in advance before the engine is started in order to activate the air-fuel ratio sensors 58 and 60 immediately after the engine is started. Therefore, if the air-fuel ratio sensors 58 and 60 are abnormal, preheating is meaningless. In a vehicle equipped with a security system for detecting an intruder in the vehicle, the start of the internal combustion engine is prohibited when the intruder is detected. Therefore, it is meaningless to perform preheating while the security system is operating. The system of the present embodiment is characterized in that by preventing preheating in such a case, the battery 75 can be prevented from being unnecessarily discharged.

  Note that the security system detects an intruder into the vehicle, for example, when a large vibration is detected in the vehicle door, or when the vehicle door is locked with a key and then unlocked from the inside of the vehicle. Inhibit starting the internal combustion engine. That is, in the former case, it is considered that the door was forcibly opened without using a regular key, and in the latter case, it was considered that the door was unlocked by, for example, putting a hand in the car from the opened door window. Therefore, in any case, it can be determined that an intruder exists. As described above, the security system is connected to the ECU 10, and the ECU 10 can monitor the operation state of the security system.

  In the system according to the present embodiment, the ECU 10 executes the routine shown in FIG. 11 together with the routine shown in FIG. 3 or FIG. 8 and the routine shown in FIG. Hereinafter, the routine shown in FIG. 11 will be described. In the routine shown in FIG. 11, steps for executing the same processes as those in the routine shown in FIG. 10 are denoted by the same reference numerals, and description thereof will be omitted. In the routine shown in FIG. 11, when the second flag F2 is set to "1" in step 350, the process of step 400 is executed next.

  In step 400, it is determined whether the security system is operating. As a result, the start of the internal combustion engine is prohibited while the security system is operating. In this case, after the process of step 105 is executed next to prohibit the preheating, the current routine ends. On the other hand, if it is determined in step 400 that the security system is not operating, the process of step 402 is executed next.

  In step 402, it is determined whether or not the sensor element 66 of the air-fuel ratio sensors 58, 60 has an abnormality. During the operation of the internal combustion engine, the ECU 10 may output a signal indicating that the air-fuel ratio sensors 58 and 60 are rich despite the fact that the fuel cut is being executed, or even though the fuel injection amount has been increased. When the air-fuel ratio sensors 58 and 60 output signals indicating lean, it is determined that an abnormality has occurred in the sensor element 66, and that fact is stored. In step 402, it is determined whether or not the air-fuel ratio sensors 58 and 60 are abnormal based on the above-mentioned memory during the previous engine operation. In step 402, if an abnormality has occurred in the sensor element 66, the processing in step 114 is executed to prohibit preheating, and then the current routine is terminated. On the other hand, if no abnormality has occurred in the sensor element 66 in step 402, the process of step 404 is executed next.

  In step 404, it is determined whether an abnormality such as a disconnection or a short circuit has occurred in the heater 68. In this embodiment, if the current supplied to the heater 68 becomes too small or too large relative to the specified value during the operation of the internal combustion engine, the disconnection or short circuit of the heater 68 is detected and the fact is stored. In step 404, it is determined whether or not the heater 68 is abnormal based on the above-described storage during the previous operation. In step 404, if an abnormality has occurred in the heater 68, the process of step 114 is executed to prohibit preheating, and then the current routine is terminated. On the other hand, if it is determined in step 404 that no abnormality has occurred in the heater 68, the pre-heat is executed in step 106 and thereafter, and then the current routine is terminated.

  As described above, according to the present embodiment, the unlock operation of the door is detected (F1 = 1), and it is determined that the driver intends to start the internal combustion engine (F2 = 1). Also, when the security system is operating or when the air-fuel ratio sensors 58 and 60 are abnormal, it is determined that it is meaningless to execute the preheat, and the execution of the preheat is prohibited. . Therefore, according to the system of the present embodiment, unnecessary discharge of the battery 75 can be prevented by not performing preheating unnecessarily, whereby the capacity of the battery 75 can be reduced, the life of the battery 75 can be extended, In addition, effects such as improvement in fuel efficiency can be obtained.

  Next, a fifth embodiment of the present invention will be described.

  As described above, in order to start the internal combustion engine smoothly, it is necessary to supply sufficient power to the starter 64. On the other hand, as the preheating is performed for a longer time, the charge amount of the battery 75 at the time of starting cranking decreases. The system according to the present embodiment can secure sufficient power for smoothly starting cranking by changing the execution time of preheating according to the state of charge of the battery 75 at the time when the door open is detected. It is characterized by points.

  The system of this embodiment has a configuration in which a battery liquid temperature sensor is provided in the hardware configuration of the second embodiment described above with reference to FIGS. The battery temperature sensor is provided in the battery 75 and outputs a signal to the ECU 10 according to the temperature of the battery solution (hereinafter, referred to as a battery solution temperature BTH).

  In the present embodiment, the ECU 10 executes the routine shown in FIG. 12 together with the routine shown in FIG. Hereinafter, the routine shown in FIG. 12 will be described. In the routine shown in FIG. 12, steps for performing the same processing as in the routine shown in FIG. 8 are denoted by the same reference numerals, and description thereof will be omitted. In the routine shown in FIG. 12, when an affirmative determination is made in step 200, the process of step 500 is executed next.

  In step 500, a preheating time period (hereinafter, referred to as a preheating permission time δ) is determined based on the battery specific gravity BS and the battery liquid temperature BTH. FIG. 13 is an example of a map that is referred to in step 500 to determine the preheat permission time δ. As described in the second embodiment, the higher the battery specific gravity BS is, the larger the charge amount of the battery 75 is. When the battery specific gravity BS is the same, the lower the battery liquid temperature BTH is, the larger the charge amount of the battery 75 is. On the other hand, the larger the charge amount of the battery 75, the longer the preheating can be performed without deteriorating the startability of the internal combustion engine. Therefore, as shown in FIG. 13, the preheat permission time δ is set to be longer as the battery specific gravity BS is higher and the battery liquid temperature BTH is lower. When the process of step 500 ends, the process of step 201 is executed next.

  In the routine shown in FIG. 12, after the preheat permission flag F1 is set to "1" in step 208, the process of step 502 is executed.

  In step 502, it is determined whether or not the timer TIMER has exceeded the preheat permission time δ. The timer TIMER is a timer that is counted up every time a unit time elapses, and is reset to “0” when the preheating execution permission flag F1 is set to “1”, that is, when the preheating is started. . Therefore, the timer TIMER indicates the elapsed time after the start of preheating. If TIMER ≧ δ is satisfied in step 502, it is determined that the preheating has been performed for the preheating permission time δ. In this case, in step 210, the preheat is stopped by resetting the preheat permission flag F1 to “0”, and then the current routine is ended. On the other hand, if TIMER ≧ δ is not satisfied in step 502, it is determined that preheating should be continued, and the current routine ends without executing the processing of step 210.

  As described above, according to the present embodiment, the power required for starting the internal combustion engine can be secured by determining the execution time of the preheating according to the state of charge of the battery 75 before the start of the preheating. Therefore, according to the system of the present embodiment, it is possible to prevent the inconvenience such as an increase in emission due to the deterioration of the startability of the internal combustion engine, and to obtain the desired effect of the preheating within a range that does not affect the startability. it can. Further, since the discharge of the battery 75 can be suppressed, cost reduction by reducing the capacity of the battery 75, improvement in the life of the battery 75, and improvement in fuel efficiency by reducing the load on the alternator can also be realized.

  Next, a sixth embodiment of the present invention will be described.

  The system of the present embodiment is characterized in that the preheating is stopped when the remaining capacity of the battery 75 becomes equal to or less than a predetermined value after the start of the preheating, so that the electric power necessary for starting the cranking of the internal combustion engine can be secured. have.

  The system according to the present embodiment is realized by the ECU 10 executing the routine shown in FIG. 14 and the routine shown in FIG. 15 in the hardware configuration of the fifth embodiment. Note that the routine shown in FIG. 14 is realized by omitting step 206 in the routine shown in FIG. Hereinafter, the routine shown in FIG. 15 will be described. When the routine shown in FIG. 15 is started, the process of step 600 is executed.

  In step 600, it is determined whether the preheat permission flag F1 is set to "1". As a result, if F1 = 1 is not satisfied, it is determined that preheating is not being performed, and the current routine is ended. On the other hand, when F1 = 1 is satisfied in step 600, the process of step 602 is executed next.

  In step 602, it is determined whether or not the starter 64 is turned on. As a result, if the starter 64 is turned on, it is determined that cranking is being started, and then, in step 604, the preheating is stopped by resetting the preheating permission flag F1 to “0”. Is terminated. On the other hand, if the starter 64 is not turned on in step 602, the process of step 606 is executed next.

  In step 606, the charge amount W of the battery 75 is detected based on the battery specific gravity BS and the battery liquid temperature BTH.

  In step 607 following step 606, a charge amount of the battery 75 necessary for starting cranking (hereinafter, referred to as a cranking required charge amount Ws) is obtained based on the water temperature THW. FIG. 16 is an example of a map referred to in this step 607 to obtain the required cranking charge amount Ws based on the water temperature THW. As described above, as the temperature of the internal combustion engine becomes lower, the power consumption of the starter 64 at the time of starting cranking increases due to an increase in friction. Therefore, as shown in FIG. 16, the required charging amount Ws for cranking is set to a larger value as the water temperature THW becomes lower. The required cranking charge amount Ws may be obtained based on the intake air temperature THA.

  In step 608 following step 607, power that can be used for preheating (hereinafter, referred to as preheating available power Wa) is obtained by subtracting the required cranking charge Ws from the charge W of the battery 75. When the processing of step 608 ends, the process proceeds to step 610.

  In step 610, it is determined whether the available power Wa is less than a predetermined reference value W0. As a result, when Wa <W0 is satisfied, it is determined that if preheating is continued, there is a possibility that the power that can be supplied to the starter 64 is insufficient and the startability is deteriorated. In this case, in step 604, the preheat is stopped by resetting the preheat permission flag F1 to “0”, and then the current routine is ended. On the other hand, if Wa <W0 is not satisfied in step 610, the current routine is terminated while preheating is continued.

  As described above, according to the present embodiment, when the preheat usable power Wa falls below a predetermined value during the execution of the preheat, the preheat is stopped, so that sufficient power can be secured at the time of starting the internal combustion engine. . Therefore, according to the system of the present embodiment, the desired effect of the preheating can be obtained within a range that does not affect the startability while preventing inconvenience such as an increase in emission due to the deterioration of the startability of the internal combustion engine. .

  Next, a seventh embodiment of the present invention will be described.

  The system of this embodiment is different from the fifth embodiment in that a battery voltage sensor for detecting a terminal voltage of the battery 75 (hereinafter, referred to as a battery voltage VB) is provided instead of the battery specific gravity sensor 92, and based on the battery voltage VB. The feature is that the charge amount of the battery 75 is estimated. FIG. 17 shows the relationship between the battery voltage VB and the charge amount W of the battery 75. As shown in FIG. 17, the battery 75 has a characteristic that the battery voltage VB decreases as the charge amount W decreases. Therefore, in the present embodiment, when the battery voltage VB falls below the predetermined value during the execution of the preheating, it is determined that the charge amount W of the battery 75 is not sufficient, and the preheating is stopped.

  Further, when the battery 75 is deteriorated, the amount of decrease in the battery voltage VB with respect to a certain amount of discharge increases. Therefore, even when the amount of decrease in the battery voltage VB after the start of the preheating exceeds a predetermined value, it is determined that the battery 75 may be deteriorated, and the preheating is stopped.

  In the system according to the present embodiment, the ECU 10 executes a routine shown in FIGS. First, the routine shown in FIG. 18 will be described. The routine shown in FIG. 18 is obtained by adding step 700 immediately before step 208 in the routine shown in FIG. In step 700, the current value of the battery voltage VB, that is, the battery voltage VB at the time when the preheating is started is stored as the initial value VBs.

  Next, the routine shown in FIG. 19 will be described. In the routine shown in FIG. 19, steps for executing the same processes as those in the routine shown in FIG. 15 are denoted by the same reference numerals, and description thereof will be omitted. In the routine shown in FIG. 19, if the starter 64 is not turned on in step 602, the process of step 710 is executed next.

  In step 710, the battery voltage VB is detected.

  In step 712 following step 710, it is determined whether the battery voltage VB is lower than a predetermined reference value VB0. As a result, if VB <VB0 is satisfied, it is determined that if preheating is continued, it may not be possible to secure the power required for cranking start, and then in step 604, the preheating permission flag F1 is set to “0”. Preheating is stopped by being reset. On the other hand, if VB <VB0 is not satisfied in step 712, the process of step 714 is executed next.

  In step 714, it is determined whether or not the voltage decrease amount ΔV (= VBs−VB) after the start of the preheating exceeds a predetermined reference value ΔV0. As a result, when ΔV> ΔV0 is satisfied, it is determined that the battery 75 may be deteriorated, and the preheating is stopped by resetting the preheating permission flag F1 to “0” in step 604 next. Is done. On the other hand, if ΔV <ΔV is not satisfied in step 714, the current routine ends while preheating is continued.

  As described above, according to the present embodiment, it is determined whether or not sufficient power for starting the internal combustion engine remains in the battery 75 based on the battery voltage VB or the voltage decrease amount ΔV during the execution of the preheating, Preheating is stopped when the power remaining in the battery 75 is not sufficient, so that sufficient power is secured at the time of starting the internal combustion engine. Therefore, according to the system of the present embodiment, it is possible to prevent the inconvenience such as an increase in emission due to the deterioration of the startability of the internal combustion engine, and to obtain the desired effect of the preheating within a range that does not affect the startability. it can.

  Next, an eighth embodiment of the present invention will be described.

  Before starting the preheating, the system according to the present embodiment obtains the preheating usable power Wa based on the charging amount W of the battery 75 and the cranking required charging amount Ws, and is consumed for the preheating during the execution of the preheating. It is characterized in that the preheat is stopped when the integrated power (hereinafter referred to as preheat integrated power Wd) exceeds the preheat usable power Wa obtained before the start of preheat. I have.

  The system according to the present embodiment is realized by the ECU 10 executing the routine shown in FIG. 20 and FIG. 21 together with the routine shown in FIG. 4 in the hardware configuration of the fifth embodiment.

  First, the routine shown in FIG. 20 will be described. In the routine shown in FIG. 20, steps for performing the same processes as those in the routine shown in FIG. In the routine shown in FIG. 20, processing of steps 800 to 804 is executed instead of the processing of step 70 of the routine shown in FIG.

  In step 800, the charge amount W of the battery 75 is detected based on the battery specific gravity BS and the battery liquid temperature BTH. When the process of step 800 ends, the process proceeds to step 802.

  In step 802, the cranking required charge amount Ws is obtained based on the water temperature THW by referring to the same map as in FIG.

  In step 804 following step 802, the preheating usable power Wa before the start of preheating is obtained by subtracting the required cranking charge Ws from the charge W of the battery 75. When the processing in step 804 ends, the processing in step 208 is executed.

  In this routine, if it is not detected in step 200 that the door has changed from the locked state to the unlocked state, then the processing of step 806 is executed.

  In step 806, it is determined whether or not the preheat permission flag F1 is set to "1", that is, whether or not the preheat is being performed. As a result, if F1 = 1 is not satisfied, the current routine ends. On the other hand, when F1 = 1 is satisfied in step 806, the process of step 808 is executed next.

  In step 808, a process of integrating the power consumption of the heater 68 during the preheating to obtain the integrated preheating power Wd is executed. When the processing in step 808 ends, the current routine ends.

  Next, the routine shown in FIG. 21 will be described. In the routine shown in FIG. 21, steps for performing the same processes as those in the routine shown in FIG. 19 are denoted by the same reference numerals, and description thereof will be omitted. In the routine shown in FIG. 21, if the starter 64 is not turned on in step 602, the process of step 850 is executed next.

  In step 850, it is determined whether or not the preheat usable power Wa is smaller than the preheat integrated power Wd. As a result, if Wa <Wd is satisfied, the current routine is terminated while preheating is continued. On the other hand, if Wa <Wd is not satisfied in step 850, the preheating is stopped by performing the process of step 604, and then the current routine is ended.

  As described above, in the present embodiment, the preheat usable power Wa is obtained in advance before the start of the preheat, and when the preheat integrated power Wd reaches the preheat usable power Wa during the execution of the preheat, the preheat is performed. Due to the suspension, sufficient electric power is secured at the time of starting the internal combustion engine. Therefore, according to the system of the present embodiment, it is possible to prevent the inconvenience such as an increase in emission due to the deterioration of the startability of the internal combustion engine, and to obtain the desired effect of the preheating within a range that does not affect the startability. it can.

  Next, a ninth embodiment of the present invention will be described. The system of this embodiment is mounted on a vehicle provided with a remote start system. FIG. 22 is a diagram illustrating a connection relationship between the ECU 10 and the remote start system in the system according to the present embodiment. As shown in FIG. 22, the remote starting system includes a remote starting signal receiver 900 and a remote starting signal transmitter 902. The remote start signal receiver 900 is connected to the ECU 10. The remote start signal transmitter 902 is carried by, for example, the owner of the vehicle.

  When a predetermined start operation is performed on the remote start signal transmitter 902 (hereinafter, a start operation on the remote start transmitter 902 is hereinafter referred to as a remote start operation), the remote start signal transmitter 902 outputs a start command signal. Transmit wirelessly. Upon receiving this start command signal, remote start receiver 900 issues a request to ECU 10 to start the internal combustion engine. The ECU 10 detects the presence or absence of a remote start operation based on the presence or absence of the start request.

  When the remote start operation is performed, the driver gets into the vehicle after a certain period of time has elapsed thereafter. For this reason, after the internal combustion engine is started, there is a certain period of time before the vehicle starts running, and it is possible to expect a temperature rise due to self-heating of the air-fuel ratio sensors 58 and 60 during that time. Therefore, in the present embodiment, when the remote start operation is performed, the target temperature Tc is set lower than in the normal case (that is, when the preheating is started by unlocking the door). As a result, the discharge power of the battery 75 is reduced.

  In this embodiment, the ECU 10 executes the routine shown in FIGS. 23 and 24 together with the routine shown in FIG. First, the routine shown in FIG. 23 will be described.

  The routine shown in FIG. 23 is executed to permit / prohibit preheating. When the routine shown in FIG. 23 is started, first, the process of step 910 is executed.

  In step 910, it is determined whether a remote start operation has been detected. As a result, if the remote start operation is detected, then in step 912, the remote start flag Fr is set to "1", and then the process of step 914 is executed. In step 914, preheating is permitted by setting the preheating permission flag F1 to "1".

  On the other hand, if the remote start operation is not detected in step 910, the process of step 916 is executed next.

  In step 916, it is determined whether a driving preparation operation (for example, an unlocking operation of a door) is detected. As a result, if an affirmative determination is made, then the remote start flag Fr is reset to “0” in step 918, and then the process of step 914 is performed to permit preheating. On the other hand, if a negative determination is made in step 916, the current routine is terminated without any further processing. It is assumed that the preheat permission flag F1 has been initialized to “0”.

  In step 920 following step 914, it is determined whether or not the remote start flag Fr is set to "1". As a result, if Fr = 1 is not established, it is determined that preheating has been permitted by the operation preparation operation, and the process of step 922 is executed next. On the other hand, when Fr = 1 is established in step 920, it is determined that preheating is permitted by the remote start operation, and the process of step 924 is executed next.

  In step 922, the target temperature Tc in preheating is set to a predetermined value Tc1. When the process of step 924 ends, the current routine ends.

  In step 924, the target temperature Tc in the preheat is set to Tc2 smaller than the predetermined value Tc1. Note that Tc2 may be a fixed value, or may be changed according to the water temperature THW, the state of charge of the battery 75, and the like. When the process of step 924 ends, the current routine ends.

  Next, the routine shown in FIG. 24 will be described. The routine shown in FIG. 24 is executed to start the internal combustion engine after the remote start operation is performed. When the routine shown in FIG. 24 is started, first, the process of step 950 is executed.

  In step 950, it is determined whether or not the remote start flag Fr has been set to "1". As a result, if Fr = 1 is not established, the current routine ends without performing any processing thereafter. In this case, thereafter, the start of the internal combustion engine is permitted according to a normal start procedure (that is, by performing a normal start operation by an ignition switch). On the other hand, when Fr = 1 is established in step 950, the process of step 952 is executed next.

  In step 952, it is determined whether or not the sensor temperature T has reached the target temperature Tc. As a result, if T ≧ Tc is satisfied, then in step 954, after the start of the internal combustion engine is permitted, the current routine ends. On the other hand, if T ≧ Tc is not satisfied in step 952, the start of the internal combustion engine is prohibited in step 956, and then the current routine is terminated.

  As described above, according to the routine in FIG. 23, the target temperature Tc when preheating is permitted by the remote start operation is set to a temperature lower than the target temperature Tc when preheating is permitted by the operation preparation operation. . That is, according to the present embodiment, at the time of the remote start operation, the target temperature Tc is set low in anticipation of the self-heating of the air-fuel ratio sensors 58 and 60 after the engine is started, so that the power required for preheating can be reduced. it can. Therefore, according to the system of the present embodiment, it is possible to activate the air-fuel ratio sensors 58 and 60 immediately after the vehicle starts running, and to suppress the discharge amount of the battery 75 to a small value.

  In the first to ninth embodiments, the battery specific gravity sensor 92 corresponds to the battery state detecting means described in the claims, and the remote start signal transmitter 900 and the remote start signal transmitter 902 correspond to the claims. Each corresponds to the described remote starting means. When the ECU 10 executes the routine shown in FIG. 4, FIG. 10, or FIG. 11, the preheating means described in the claims is executed in the steps 152, 156, 158, 160, or 160 of the routine shown in FIG. By executing the processing of steps 300 and 304 of the routine shown in the drawings, the starting intention determination means described in the claims is executed by steps 201, 202 and 204 of the routine shown in FIG. 8, step 607 of the routine shown in FIG. The starter power estimation means described in the claims by executing the processing of step 802 of the routine shown in FIG. 20 executes the processing of steps 400, 402, and 404 of the routine shown in FIG. 11 executes the processing of step 105 of the routine shown in FIG. Preheating prohibition means described in the claims by Rukoto is, the remote control during startup means described in the claims by performing the routine shown in FIGS. 23 and 24, are realized, respectively.

  In the first to ninth embodiments, the temperature of the heater 68 is obtained based on the heater resistance R, and this temperature is used as the sensor temperature T. However, the method of obtaining the sensor temperature T is not limited to this. is not. For example, the sensor element 66 has a characteristic that the impedance decreases as the sensor temperature T increases. Therefore, the sensor temperature T may be obtained by applying an AC voltage of a predetermined frequency to the sensor element 66 and measuring the impedance of the sensor element 66 from the relationship between the applied voltage and the current. During the stop of the engine, the oxygen concentration in the exhaust passage 58 is kept constant (a value equal to the oxygen concentration at atmospheric pressure). On the other hand, the current flowing through the sensor element 66 under the condition that the oxygen concentration is kept constant increases as the sensor temperature T increases until the sensor temperature T reaches the activation temperature. Therefore, the sensor temperature T can be obtained based on the sensor current I before the engine is started.

  Further, in the above-described embodiment, the oxygen concentration is detected by the air-fuel ratio sensors 62 and 64 in which the sensor current I continuously changes according to the air-fuel ratio. However, the present invention is not limited to this. , 64, may be replaced by an O2 sensor that outputs a two-stage signal of rich / lean in accordance with the air-fuel ratio.

  Further, in the above-described embodiment, the duty amount of the power supply to the heater 68 is controlled. However, the present invention is not limited to this, and the power supply may be controlled by changing the current value linearly.

1 is a system configuration diagram of an internal combustion engine to which a heater control device for an air-fuel ratio sensor according to the present invention is applied. FIG. 2 is a diagram illustrating an internal configuration of an air-fuel ratio sensor included in the system of the present embodiment, together with a connection circuit with an ECU. 4 is a flowchart of a routine executed by an ECU to permit preheating in the first embodiment of the present invention. 4 is a flowchart of a routine executed by an ECU to perform preheating in the present embodiment. 4 is a flowchart of a routine executed by the ECU to stop preheating when it is determined that the driver does not intend to start the internal combustion engine in the present embodiment. FIG. 9 is a diagram illustrating sensors and the like connected to an ECU according to a second embodiment of the present invention. It is a figure which shows the relationship between battery specific gravity BS and starting time Te. 4 is a flowchart of a routine executed by an ECU to permit preheating in the embodiment. FIG. 13 is a flowchart of a routine executed by an ECU to perform a second condition determination for permitting preheating in a third embodiment of the present invention. 4 is a flowchart of a routine executed by an ECU to perform preheating in the present embodiment. FIG. 13 is a flowchart of a routine executed by the ECU to perform preheating and to stop the preheating when a predetermined condition is satisfied in the fourth embodiment of the present invention. FIG. 15 is a flowchart of a routine executed by an ECU to permit preheating in a fifth embodiment of the present invention. 4 is a map referred to in the present embodiment to determine the energization time δ in preheating from the battery specific gravity BS and the battery liquid temperature BTH. 15 is a flowchart of a routine executed by an ECU to permit preheating in a sixth embodiment of the present invention. 4 is a flowchart of a routine executed by an ECU to prohibit preheating in the embodiment. In this embodiment, it is a map referred to in order to obtain the required cranking charge amount Ws from the water temperature THW. FIG. 15 is a map referred to for calculating a battery charge amount W from a battery voltage VB in a seventh embodiment of the present invention. 4 is a flowchart of a routine executed by an ECU to permit preheating in the embodiment. 5 is a flowchart of a routine executed by the ECU to prohibit preheating in the embodiment. It is a flowchart of the routine which ECU performs in 8th Example of this invention to permit preheating. 5 is a flowchart of a routine executed by the ECU to prohibit preheating in the embodiment. It is a figure showing the connection relation between ECU and the remote starting system in a 9th example of the present invention. It is a flowchart of the routine which ECU performs in 9th Example of this invention to permit preheating. 5 is a flowchart of a routine executed by an ECU to start the internal combustion engine after a remote start operation in the embodiment.

Explanation of reference numerals

10 ECU
58, 60 Air-fuel ratio sensor 68 Heater 92 Battery specific gravity sensor 900 Remote start signal receiver 902 Remote start signal transmitter

Claims (10)

A heater control device that controls energization of a heater included in an air-fuel ratio sensor provided in an internal combustion engine,
Preheating means for energizing the heater before starting the internal combustion engine,
Battery state detection means for detecting the state of the battery;
Power supply control means for controlling a power supply state to the heater by the preheating means based on a state of the battery;
A heater control device for an air-fuel ratio sensor for an internal combustion engine, comprising: The heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 1,
The heater control device for an air-fuel ratio sensor for an internal combustion engine, wherein the power supply control means changes a power supply time to the heater by the preheating means based on a state of the battery. The heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 1,
With starter power consumption prediction means for predicting the power consumption of the starter at the time of starting the internal combustion engine,
The heater control device for an air-fuel ratio sensor for an internal combustion engine, wherein the energization control unit controls an energization state of the heater by the preheating unit based on the predicted power consumption and a state of the battery. . A heater control device that controls energization of a heater included in an air-fuel ratio sensor provided in an internal combustion engine,
Preheating means for energizing the heater before starting the internal combustion engine,
Starter power prediction means for predicting the power consumption of the starter at the time of starting the internal combustion engine,
Based on the predicted power consumption, energization control means for controlling the energization state to the heater by the preheating means,
A heater control device for an air-fuel ratio sensor for an internal combustion engine, comprising: The heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 4,
The heater control device for an air-fuel ratio sensor for an internal combustion engine, wherein the energization control unit prohibits or stops energization of the heater by the preheating unit when the predicted power consumption exceeds a predetermined value. The heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 4,
The power supply control means reduces the amount of power supply to the heater by the preheating means when the predicted power consumption exceeds a predetermined value, as compared with a case where the predicted power consumption does not exceed the predetermined value. Heater control device for fuel ratio sensor. A heater control device that controls energization of a heater included in an air-fuel ratio sensor provided in an internal combustion engine,
Preheating means for energizing the heater before starting the internal combustion engine,
Preheating unnecessary state detecting means for detecting a predetermined state in which energization of the heater by the preheating means is unnecessary,
When the predetermined state is detected, a preheating prohibiting unit that prohibits the heater from being energized by the preheating unit,
A heater control device for an air-fuel ratio sensor for an internal combustion engine, comprising: The heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 7,
The heater control device for an air-fuel ratio sensor for an internal combustion engine, wherein the predetermined state is a state where an abnormality has occurred in the air-fuel ratio sensor. The heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 7,
The internal combustion engine is mounted on a vehicle including a security system that operates when an intruder is detected in the vehicle,
The heater control device for an air-fuel ratio sensor for an internal combustion engine, wherein the predetermined state is a state in which the security system is operating. A heater control device that controls energization of a heater included in an air-fuel ratio sensor provided in an internal combustion engine,
Preheating means for energizing the heater before starting the internal combustion engine,
Remote starting means for starting the internal combustion engine by remote control;
When the starting operation is performed by the remote start unit, the preheating unit supplies power to the heater with a smaller amount of power than a normal amount of power, and then starts the internal combustion engine during remote operation. Means,
A heater control device for an air-fuel ratio sensor for an internal combustion engine, comprising:

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