JP2000235014A - Heater control device of air/fuel ratio sensor for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress discharge of a battery caused by preheating, in the case of a heater control device for an air/fuel sensor having the preheating function of heating the air/fuel sensor prior to the start of an internal combustion engine. SOLUTION: When unlocking operation of a door is detected, preheating is permitted by setting up a flag F1 at '1'. Even when the flag F1 is at '1' (step 150), a judgement is made that starting is not intended in the case that an engine hood is open (step 152), in the case that a fuel lid is open (step 156), in the case that vehicle speed exceeds a fixed value 0 (step 158), or in the case that a fixed amount of time has passed with the door opened (step 160), and the preheating is suspended by resetting the flag F1 at '1' (step 154).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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.

[0002]

2. Description of the Related Art In an internal combustion engine, air-fuel ratio feedback control for controlling the air-fuel ratio toward a stoichiometric air-fuel ratio is performed by correcting the fuel injection amount based on the air-fuel ratio of an 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 deterioration of the fuel efficiency is prevented. 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
A heater for heating the sensor element to the activation temperature is built in. After energization of the heater of the air-fuel ratio sensor is started, until the sensor temperature reaches the activation temperature,
It takes some time before the air-fuel ratio feedback control based on the output signal of the air-fuel ratio sensor becomes possible. 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.

[0003] For example, in the air-fuel ratio control device disclosed in Japanese Patent Application Laid-Open No. 5-202785, the start of the internal combustion engine is predicted when the door of the vehicle is detected, and the preheating of the heater of the air-fuel ratio sensor is started. I do. When the sensor temperature reaches a predetermined target temperature, the power supply to the heater is stopped.

[0004]

Incidentally, even when a door open is detected, the internal combustion engine is not always started. In some cases, it may not be 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 the door open is detected, the preheating is always performed, so that the battery may be unnecessarily discharged.

[0005] The present invention has been made in view of the above problems, and has as its object to provide a heater control device for an air-fuel ratio sensor for an internal combustion engine, which can avoid the above problems.

[0006]

The above object is achieved by the present invention.
A heater control device for controlling energization of a heater provided in an air-fuel ratio sensor provided in an internal combustion engine, comprising: a preheating means for energizing the heater before starting the internal combustion engine; An internal combustion engine air conditioner comprising: a start intention determining means for determining the presence or absence of a start intention; and an energization control means for controlling an energization state of the heater by the preheating means based on a determination result by the start intention determination means. This is achieved by the heater control device of the fuel ratio sensor.

According to the first aspect of the present invention, the energization control means controls the energization state of the heater by the preheating means based on whether the driver intends to start the internal combustion engine. The operation of supplying electricity to the heater by the preheating means is hereinafter referred to as "preheating". That is, the presence or absence of a start intention is reflected in the state of energization of the heater by the preheating means. Therefore, according to the present invention, it is possible to prevent the heater from being supplied with unnecessarily large electric power during the preheating, thereby suppressing the discharge of the battery.

In this case, as set forth in claim 2, in the heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 1, the energization control means determines that there is no start intention. The energization of the heater by the preheating means may be stopped or prohibited. Also,
According to a third aspect of the present invention, in the heater control device for an air-fuel ratio sensor for an internal combustion engine according to the first aspect, the energization control means determines that the starting intention is present when it is determined that the starting intention is not present. The amount of power supplied to the heater by the preheating means may be reduced as compared with the case where the preheating is performed.

Further, the above object is to provide a heater control device for controlling energization of a heater provided in an air-fuel ratio sensor provided in an internal combustion engine, wherein Preheating means for energizing the heater;
A heater control device for an air-fuel ratio sensor for an internal combustion engine, comprising: battery state detection means for detecting a state of a battery; and conduction control means for controlling a conduction state to the heater by the preheating means based on the state of the battery. Is achieved by

According to a fourth aspect of the invention, the power supply control means controls the power supply to the heater by the preheating means based on the state of the battery. That is, since the state of the battery is reflected in the state of current supply to the heater by the preheating means, the battery is prevented from being excessively discharged during the preheating. In this case, as set forth in claim 5, in the heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 4, the energization control unit controls the heater by the preheating unit based on a state of the battery. The energization time may be changed.

Further, as described in claim 6, claim 4
The heater control device for an air-fuel ratio sensor for an internal combustion engine according to the above, further including a starter power consumption prediction unit that predicts power consumption of a starter at the time of starting the internal combustion engine, and the energization control unit includes the predicted power consumption The state of power supply to the heater by the preheating means may be controlled based on the state of the battery.

According to the present invention, the power supply control means controls the power supply state to the heater by the preheating means based on the predicted power consumption of the starter and the state of the battery. That is, 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, so that the starter can reliably start the internal combustion engine.

[0013] The present invention also provides a heater control device for controlling energization of a heater provided in an air-fuel ratio sensor provided in an internal combustion engine, wherein the heater control device controls the energization of the heater before the internal combustion engine is started. Preheating means for energizing the heater;
An internal combustion engine comprising: starter power prediction means for predicting power consumption of a starter when the internal combustion engine is started; and power supply control means for controlling a power supply state to the heater by the preheating means based on the predicted power consumption. This is achieved by the heater control device of the engine air-fuel ratio sensor.

According to a seventh aspect of the present invention, the power supply control means controls the power supply to 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, as set forth in claim 8, in the heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 7, the energization control means may determine whether the predicted power consumption exceeds a predetermined value. Alternatively, energization of the heater by the preheating means may be prohibited or stopped. According to a ninth aspect of the present invention, in the heater control device for an air-fuel ratio sensor for an internal combustion engine according to the seventh aspect, the energization control means determines whether or not the predicted power consumption exceeds a predetermined value. Alternatively, the amount of electricity supplied to the heater by the preheating means may be reduced.

According to a tenth aspect of the present invention, there is provided a heater control device for controlling energization of a heater provided in an air-fuel ratio sensor provided in an internal combustion engine, wherein A preheating means for energizing the heater, a preheating unnecessary state detecting means for detecting a predetermined state in which energization of the heater by the preheating means is undesirable, and the heater by the preheating means when the predetermined state is detected. This is achieved by a heater control device for an air-fuel ratio sensor for an internal combustion engine, comprising:

In a ninth aspect of the present invention, the preheating inhibiting means inhibits the preheating in a predetermined state in which the execution of the preheating is not desired. 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, as described in claim 11, in the heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 10, the predetermined state may be a state in which an abnormality has occurred in the air-fuel ratio sensor. .

According to a twelfth aspect of the present invention, in the heater control device for an air-fuel ratio sensor for an internal combustion engine according to the tenth aspect, the internal combustion engine operates when an intruder in the vehicle is detected. And the predetermined state may be a state in which the security system is operating.

Further, the above object is to provide a heater control device for controlling energization of a heater provided in an air-fuel ratio sensor provided in an internal combustion engine, wherein Preheating means for energizing the heater, remote starting means for instructing the start of the internal combustion engine by remote operation, and when the starting operation by the remote starting means is performed, the preheating means causes This is achieved by a heater control device for an air-fuel ratio sensor for an internal combustion engine, comprising: a remote operation start means for starting the internal combustion engine after energizing the heater with a small energization amount.

According to the thirteenth aspect of the present invention, when the remote start means commands 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. . Therefore, during the period before the start of the internal combustion engine and before the start of traveling, an increase in the temperature due to the self-heating of the air-fuel ratio sensor can be expected.
Therefore, according to the present invention, when the start operation by the remote start means is performed, the start 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 preheat is reduced,
Battery discharge is suppressed.

[0021]

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 1
2 is provided. 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. E
The CU 10 determines the water temperature T based on the output signal of the water temperature sensor 18.
HW is detected.

A piston 20 is provided inside the cylinder 14. The piston 20 can slide inside the cylinder 14 in the vertical direction in FIG. A cylinder head 22 is fixed to an upper portion 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 are both
8 is open. 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 has an intake valve 34 and an exhaust valve 36. Intake port 24 and exhaust port 26
A valve seat for the intake valve 34 and the exhaust valve 36 is formed at the opening to the combustion chamber 28, respectively. Intake valve 3
4 and the exhaust valve 36 are separated from and seated on each valve seat,
The intake port 24 and the exhaust port 26 are opened and closed, respectively.

The intake port 24 has an intake manifold 3
8 are in communication. A fuel injection valve 40 is provided in the intake manifold 38. The fuel injection valve 40 is ECU1
Fuel is injected into the intake manifold 38 according to a command signal given from zero. 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. Catalytic converter 56
Purifies the exhaust gas by reacting hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (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 has 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 controls the rotation speed of the internal combustion engine (hereinafter, referred to as engine rotation speed NE) based on the output signal of the rotation speed sensor 62.
Is detected. Further, the internal combustion engine includes a starter 64. The starter 64 realizes a cranking start of the internal combustion engine by being supplied with an 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 have a sensor element 66 therein made of a material such as zirconia.
And a heater 68 for heating the sensor element 66. 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. When the constant voltage is applied to the sensor element 66 in this manner, a current flowing through the sensor element 66 (hereinafter, referred to as a sensor current I)
Indicates that the temperature of the sensor element 66 (hereinafter referred to as the sensor temperature T) is a predetermined activation temperature Te (for example, from 650 ° C. to 7
When the temperature is equal to or greater than (00 ° C.), the pressure 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 a power supply control circuit 74. Energization control circuit 74
Performs duty control of a current supplied 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. ECU
10 detects the resistance value of the heater 68 (hereinafter, referred to as heater resistance R) based on these signals.

The ECU 10 includes a door lock switch 8
0, a fuel lid switch 82, and an engine hood switch 84 are connected. The door lock switch 80 is a switch that is turned on only when the vehicle door is unlocked. Further, 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 opened. 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.

During the operation of the internal combustion engine, the ECU 10 controls the amount of power supplied to the heater 68 so 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. Control. Note that the heater resistance R changes according to the temperature of the heater 68. Therefore, ECU1
0 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, the sensor temperature T becomes the activation temperature T
In a state where the current is maintained at e or more, the current flowing through the sensor element 66 changes in accordance with the oxygen concentration. Therefore, ECU1
In the case of 0, the oxygen concentration in the exhaust passage 54, that is, the air-fuel ratio can be detected 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. Is maintained within a predetermined range near the stoichiometric air-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 are
Can be more effectively removed. 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
Since the temperature has almost dropped to the outside temperature, 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 and 60 are controlled. It is conceivable to start energizing the heater 68. Hereinafter, energization of the heater 68 performed before the engine is started is performed by the air-fuel ratio sensor 58,
60 preheat. The air-fuel ratio sensor 58,
If the air-fuel ratio sensor 60 has a different configuration, for example, only the air-fuel ratio sensor 58 has a heater 68, the 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 will be discharged unnecessarily if the internal combustion engine is not started. On the other hand, in the system of the present embodiment, after the preheating is started, when the driver determines that the driver does not intend to start the internal combustion engine, the preheating is stopped, so that the battery 75 becomes unnecessary. It is characterized in that discharge can be prevented.
Hereinafter, the specific processing executed by the ECU 10 in this 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 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.
0 is executed. In step 100, it is determined whether the door has changed from the locked state to the unlocked state. As a result, when an affirmative determination is made, it is determined that an unlock operation of the door has been performed, and then at step 102
Is performed. On the other hand, in step 100,
If a negative determination is made, the current routine ends without any further processing. Step 10
At 0, instead of detecting unlocking of the door, it may be detected that the door has been opened.

At 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 in steps 100 and 102, the preheating is started when the door is unlocked. When the process of step 102 is completed, the current routine is completed.

Next, the routine shown in FIG. 4 will be described. When the routine shown in FIG.
4 is executed. In step 104, it is determined whether 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 holds 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. In the following step 108, the sensor temperature T is set to the target temperature Tc.
Is determined. Note that the target temperature T
c is higher than the activation temperature Te of the sensor element 66,
In addition, the temperature is set to such a degree that the sensor element 66 is not damaged. If it is determined in step 106 that T> Tc, then in step 110, the duty ratio HTduty is reduced by α, so that the heater 6
After the amount of energization to 8 has been reduced, the current routine ends. 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, and then the current routine is terminated. . According to the processing of steps 108, 110, 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 or not 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”. Step 154
Is completed, the current routine ends. On the other hand, if it is determined in step 152 that the engine hood is not open, the process of step 156 is executed.

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 does not intend to start the internal combustion engine, and the pre-heating is stopped by executing the process of step 154, and then the current routine is ended. On the other hand, if the fuel lid is not opened in step 156, then step 1
Step 58 is executed.

In step 158, the vehicle speed V is set to a predetermined value V0.
It is determined whether or not this is the case. 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 does not intend to start the internal combustion engine, and the pre-heating is stopped by executing the process 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 cleaning and the like in the vehicle are being performed. In this case, it is determined that the driver does not intend to start the internal combustion engine, and the pre-heating is stopped by executing the process 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 door unlock operation 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 has no intention to start the internal combustion engine, the preheating is stopped. Therefore, according to the present embodiment, when the driver does not intend to start the internal combustion engine, the preheating is not continued, so that the battery 75
Is prevented from being unnecessarily discharged. That is, according to the present embodiment, the preheating is performed only when the probability of starting the internal combustion engine 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 the minimum necessary.

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, so that the fuel efficiency can be reduced. Can be improved. Further, since the battery capacity can be reduced, the cost of the system can be reduced.

In the above-described embodiment, it is determined that the driver has no intention to start during the inspection of the engine room, during refueling, during manual pushing, and when performing inspection and cleaning in the vehicle. The situations where it can be determined that there is no such information are not limited to these. For example, after the door is closed,
If the internal combustion engine is not started even after a certain period of time while the car radio is on, it may be determined that the driver is not willing to start, assuming that the passenger is waiting. In addition, when the movement of the driver is detected by a seating sensor or the like provided in the driver's seat and 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 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, and it is determined that there is no intention to start the internal combustion engine. At this point, the amount of energization during preheating may be reduced, for example, 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 a 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 prohibited, thereby suppressing the discharge of the battery 75 and ensuring the internal combustion engine. It is characterized in that starting can be guaranteed.

FIG. 6 is a connection diagram of various sensors and the like to the ECU 10 in this embodiment. As shown in FIG. 6, the system of this 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. An intake air temperature sensor 88 is disposed in the intake pipe 44 and has an intake air temperature T.
A signal corresponding to the HA is output 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.
Outlines 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 a start time Te) when the internal combustion engine is in a low temperature state. Is 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, the larger the specific gravity BS of the battery (ie, the larger the charge capacity of the battery 75), the smaller the electric power that can be supplied to the starter 64, and thus the longer the start time Te. 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. Starting time T
If e is long, the startability is deteriorated, causing an increase in emissions in the exhaust gas. Further, if the start time Te exceeds a certain value, the engine cannot be started due to the adhesion of fuel to the ignition plug 30. Become.

Therefore, in the present embodiment, when the internal combustion engine is in a low temperature state, the ECU 10 determines that the power consumption of the starter 64 when 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 the preheating will deteriorate the engine startability or the starting will be impossible, and the preheating will be prohibited.

In the present embodiment, the ECU 10 is configured as shown in FIG.
The routine shown in FIG. 8 is executed together with the routine shown in FIG. Hereinafter, the routine shown in FIG. 8 will be described. FIG.
Is activated, the processing 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, the post-stop elapsed time Ta
Is greater than 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, the battery specific gravity BS
Is smaller than the reference value BS0. As a result, when BS <BS0 is satisfied, the preheat is prohibited in step 208 by resetting the preheat permission flag F1 to “0”.
This routine is ended. On the other hand, step 20
If a negative determination is made in any of 1 to 206, then in step 210, the preheat permission flag F1
Is set to “1”, the preheat is permitted, and then the current routine is ended.

As described above, according to the routine shown in FIG. 8, the water temperature THW is smaller than the reference value THW0, the intake air temperature THA is smaller than the reference value THA0, and the post-stop elapsed time Ta is smaller than the predetermined reference value. In this case, the internal combustion engine is in a low temperature state, and it is determined that the power consumption of the starter 64 is large. And further, the battery specific gravity B
If S is smaller than the reference value BS0, it is determined that the charge capacity of the battery 75 is insufficient for realizing good engine startability, and execution of preheating is prohibited. As described above, in the present embodiment, the possibility of preheating is determined in consideration of the 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 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, as in the case of the first embodiment, the discharge of the battery 75 can be suppressed.
, The life of the battery 75 can be prolonged, and the fuel consumption can be improved by reducing the load on the alternator. In the second embodiment, the preheating is prohibited when all of the above conditions are satisfied.
If any one of the conditions is satisfied, a start failure may occur. Therefore, in such a case,
If any one of the above conditions is satisfied, the preheating may be prohibited. In this case, preheating is more likely to be prohibited than in the second embodiment, so that
Each of the reference values THW0, THA0, Ta0, and BS0 may be set to a value smaller than that in the second embodiment to prevent the preheating from being excessively prohibited.

In the second embodiment, the preheat is prohibited when the following conditions are satisfied.
However, the present invention is not limited to this, and when the condition (1) to (5) is satisfied, the amount of power supplied during preheating may be reduced by lowering the target temperature Tc. Next, a third embodiment of the present invention will be described.

The system of the present embodiment is different from the hardware configuration of the second embodiment shown in FIGS. 1, 2 and 6 in that
Even when a door unlocking operation is detected, if it is determined that the driver does not intend to start the engine, preheating is prohibited, and unnecessary power consumption can be prevented. are doing. 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 is terminated. 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 fuel is being supplied 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 at step 304, then at step 306, the second permission flag F2 is set to "1", and then the current routine is terminated.

Next, the routine shown in FIG. 10 will be described. In the routine shown in FIG.
The steps that execute the same processing as the routine shown in (1) are denoted by the same reference numerals and description thereof is 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, the second permission flag F2
Is set to "1". As a result, when F2 = 1 is satisfied, after the processing for performing the preheating is performed in step 106 and thereafter,
This 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 is terminated.

As described above, in this embodiment, when the door unlock operation is detected (F1 = 1) and it is determined that the driver intends to start the internal combustion engine (F2 = 1). Only preheating is performed. For this reason, when the driver has no intention of starting, 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,
Air-fuel ratio sensors 58 and 60 after engine start due to preheating
While suppressing the discharge of the battery 75, thereby achieving cost reduction by reducing the capacity of the battery 75, prolonging the life of the battery 75, and improving fuel efficiency by reducing the load on the alternator. be able to.

In the third embodiment, the preheating is prohibited when it is determined that the engine room is being inspected or the fuel is being supplied. However, as in the first embodiment, the preheating is prohibited. Alternatively, when it is determined that the vehicle is waiting for a passenger, the preheat 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,
Further, it is realized by connecting a security system to the ECU 10. As described above, the preheating is a process for energizing the heater 68 in advance before starting the engine in order to activate the air-fuel ratio sensors 58 and 60 immediately after starting the engine. Therefore, if the air-fuel ratio sensors 58 and 60 are abnormal, it is meaningless to perform the preheating. 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.

The security system is, 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, an intruder in the vehicle is detected and the start of the internal combustion engine is prohibited. In other words, in the former case, it is considered that the door was forcibly opened without using a regular key,
In the latter case, for example, it is considered that the vehicle has been unlocked by putting a hand into the vehicle through the opened door window, so that it can be determined that an intruder exists in any case. As described above, the security system uses the ECU 10
The ECU 10 can monitor the operation state of the security system.

In the system of this 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.
If 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, then step 1
After the preheating is prohibited by performing the processing of step 05, 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, the air-fuel ratio sensor 58
It is determined whether or not the 60 sensor element 66 has an abnormality. During the operation of the internal combustion engine, for example, the ECU 10 outputs a signal indicating that the air-fuel ratio sensors 58 and 60 indicate rich despite the fact that the fuel cut is executed, or despite the fact that the fuel injection amount has been increased. Air-fuel ratio sensor 5
When the signals 8 and 60 output a signal indicating lean, it is determined that an abnormality has occurred in the sensor element 66, and the 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-described memory during the previous engine operation. In step 402, the sensor element 66
In this case, the pre-heating is prohibited by executing the processing of step 114, 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 or not the heater 68 has an abnormality such as disconnection or short circuit. 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. If it is determined in step 404 that the heater 68 has an abnormality, the process of step 114 is executed to prohibit the preheating, and then the current routine ends. On the other hand, in step 404, the heater 6
If no abnormality has occurred in Step 8, the pre-heat is executed in Step 106 and thereafter, and then the current routine is terminated.

As described above, according to this embodiment, the unlocking operation of the door is detected (F1 = 1), and it is determined that the driver intends to start the internal combustion engine (F2 = 1).
Even in the case where the security system is operating or the air-fuel ratio sensors 58 and 60 are abnormal, it is determined that performing the preheating is meaningless, and the preheating is not performed. Execution is prohibited. Therefore, according to the system of the present embodiment, unnecessary discharge of the battery 75 can be prevented by not performing unnecessary preheating, thereby reducing the capacity of the battery 75,
Effects such as prolonging the life of the battery 75 and improving 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, the longer the preheat is performed, the smaller the charge amount of the battery 75 becomes at the time of starting cranking.
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 the present embodiment is different from the hardware configuration of the second embodiment shown in FIGS. 1, 2 and 6 in that
It has a configuration provided with a battery liquid temperature sensor. The battery fluid temperature sensor is disposed on the battery 75 and has a battery fluid temperature (hereinafter referred to as a battery fluid temperature BTH).
Is output to the ECU 10. 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, the battery specific gravity BS
Based on the battery fluid temperature BTH, the length of time for performing preheating (hereinafter, referred to as preheating permission time δ) is determined. 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 specific gravity BS of the battery 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, as the charge amount of the battery 75 increases,
Preheating can be performed for a long time 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 the timer TIMER has exceeded the preheat permission time δ. The timer TIMER is a timer that is counted up each time a unit time elapses, and a preheat execution permission flag F
It is reset to "0" when 1 is set to "1", that is, when preheating is started. Therefore,
The timer TIMER indicates the elapsed time after the start of preheating. In step 502, TIMER ≧ δ
Holds, the preheat is the preheat permission time δ
Is determined to have been executed. In this case, after the preheating is stopped in step 210 by resetting the preheating permission flag F1 to “0”,
This 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 preheat in accordance with the state of charge of the battery 75 before the start of the preheat. Therefore, according to the system of the present embodiment, it is possible to obtain the desired effect by preheating within a range that does not affect the startability while preventing inconveniences such as an increase in emission due to deterioration of the startability of the internal combustion engine. 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 according to 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 electric power necessary for starting 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 together with the hardware configuration of the fifth embodiment. It should be noted 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.
00 is executed.

At step 600, it is determined whether or not 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 terminated. 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. Next, in step 604, the preheat is stopped by resetting the preheat permission flag F1 to “0”, and this time, 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 battery specific gravity BS
And the battery 75 based on the battery fluid temperature BTH.
Is detected. In step 607 following step 606, a charge amount of the battery 75 necessary for starting cranking (hereinafter, referred to as a required cranking charge amount Ws) is obtained based on the water temperature THW. FIG.
6 is an example of a map referred to in this step 607 to obtain the cranking required 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. Note that the required cranking charge amount Ws is calculated based on the intake air temperature TH.
It may be determined based on A.

In step 608 following step 607, the power that can be used for preheating (hereinafter referred to as preheat usable 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 the preheating is continued, the power that can be supplied to the starter 64 is insufficient and the startability may be 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 terminated.
On the other hand, if Wa <W0 is not satisfied in step 610, this routine is ended 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 is secured when the internal combustion engine is started. be able to. 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 the present embodiment is different from the fifth embodiment in that
A feature is 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 a charge amount of the battery 75 is estimated based on the battery voltage VB. ing. FIG. 17 shows the relationship between the charge amount W of the battery 75 and the battery voltage VB. 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 this embodiment, the battery voltage V
When B falls below a predetermined value, the charge amount W of the battery 75
Is judged to be insufficient, and the preheating is stopped.

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, the battery voltage VB after the start of preheating
Also, when the amount of decrease exceeds a predetermined value, it is determined that the battery 75 may be deteriorated, and the preheating is stopped. In the system of the present embodiment, the ECU 10
8 and the routine shown in FIG. First, FIG.
Will be described. The routine shown in FIG. 18 is different from the routine shown in FIG.
Step 700 is added immediately before step 8. 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.
Steps that execute the same processes as in the routine shown in FIG. 5 are denoted by the same reference numerals, and description thereof is omitted. In the routine shown in FIG.
If is not turned on, the process of step 710 is executed next.

At 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 electric power required for cranking start. Next, in step 604, the preheating permission flag F1 is set to “0”. Preheating is stopped by being reset. On the other hand, in step 712, VB <
If VB0 is not satisfied, the process of step 714 is executed next.

In step 714, the amount of voltage drop ΔV (= VBs−VB) after the start of preheating is reduced to a predetermined reference value ΔV.
It is determined whether the value is greater than zero. As a result, ΔV
If> ΔV0 is satisfied, it is determined that the battery 75 may have deteriorated, and then the preheating is stopped by resetting the preheating permission flag F1 to “0” in step 604. On the other hand, if ΔV <ΔV is not satisfied in step 714, the current routine is terminated while preheating is continued.

As described above, according to the present embodiment, sufficient electric power for starting the internal combustion engine is obtained based on the battery voltage VB or the amount of voltage decrease ΔV during the execution of preheating.
It is determined whether or not the battery 5 remains, and if the power remaining in the battery 75 is not sufficient, the preheating is stopped, so that sufficient power is secured when the internal combustion engine is started. Therefore, according to the system of the present embodiment, it is possible to obtain the desired effect by preheating within a range that does not affect the startability while preventing inconveniences such as an increase in emission due to deterioration of the startability of the internal combustion engine. it can.

Next, an eighth embodiment of the present invention will be described. Before starting the preheating, the system according to the present embodiment has the charge amount W of the battery 75 and the charge amount Ws required for cranking.
Is calculated based on the preheat available power Wa, and the power consumed for the preheat during execution of the preheat is integrated, and the integrated power (hereinafter, referred to as preheat integrated power Wd) is calculated before the start of the preheat. It is characterized in that the preheating is stopped when the preheating usable power Wa obtained in step (1) is exceeded.

The system of this embodiment is realized by the ECU 10 executing the routines shown in FIGS. 20 and 21 in addition to 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. 18 are denoted by the same reference numerals, and description thereof will be omitted. FIG.
In the routine shown in FIG. 0, the 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 battery specific gravity BS
And the battery 75 based on the battery fluid temperature BTH.
Is detected. When the processing in step 800 ends, the flow advances to step 802. In step 802, by referring to the same map as in FIG.
The cranking required charge amount Ws is obtained based on the HW.

In step 804 following step 802, the preheat 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".
It is determined 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.

At step 808, a process is performed for integrating the power consumption of the heater 68 in the preheating to obtain the integrated preheating power Wd. When the processing in step 808 ends, the current routine ends. Next, FIG.
1 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 has not been turned on in step 602, the process of step 850 is executed next.

At step 850, it is determined whether or not preheat usable power Wa is smaller than 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 the preheat integrated power Wd during the execution of the preheat.
Has reached the preheat usable power Wa, the preheating is stopped, 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 obtain the desired effect by preheating within a range that does not affect the startability while preventing inconveniences such as an increase in emission due to deterioration of the startability of the internal combustion engine. 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. Remote start signal receiver 90
0 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 remote start signal transmitter 902 (hereinafter, a start operation on remote start transmitter 902 is referred to as a remote start operation), remote start signal transmitter 902 is started. The command signal is transmitted 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 the remote start operation based on the presence or absence of the start request.

If the remote start operation is performed,
After some time, the driver will get into the vehicle. 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 the door unlocking operation). 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.
Executed to prohibit. 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, the 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 next executed. In step 916, it is determined whether or not a driving preparation operation (for example, a door unlocking operation) has been detected. As a result, if a positive determination is made, the remote start flag Fr is reset to "0" in step 918, and then the process of step 914 is performed to permit preheating. Step 9
If a negative determination is made in step 16, 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 performed next.

In step 922, the target temperature Tc in preheating is set to a predetermined value Tc1. Step 9
When the process of 24 is completed, the current routine is completed. In step 924, the target temperature Tc in the preheating 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 the normal start procedure (that is, by performing the normal start operation by the ignition switch). On the other hand, when Fr = 1 is established in step 950, the process of step 952 is executed next.

At step 952, it is determined whether or not the sensor temperature T has reached the target temperature Tc. as a result,
If T ≧ Tc holds, then in step 954, after the start of the internal combustion engine is permitted, the current routine is ended. 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 shown in FIG.
The target temperature Tc when the preheating is permitted by the remote start operation is set to a temperature lower than the target temperature Tc when the 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 is connected to the battery state detecting means described in the claims by a remote start signal transmitter 90.
0 and the remote start signal transmitter 902 respectively correspond to the remote start means described in the claims. Also,
When the ECU 10 executes the routine shown in FIG. 4, FIG. 10, or FIG. 11, the preheating means described in the appended claims executes steps 152, 1 in the routine shown in FIG.
56, 158, 160 or the processing of steps 300, 304 of the routine shown in FIG. 9 is executed, whereby the starting intention determining means described in the claims is executed by the steps 201, 202, 204 of the routine shown in FIG. By executing the processing of step 607 of the routine shown in FIG. 15 or step 802 of the routine shown in FIG. 20, the starter power estimating means described in the claims makes the steps 400, 402, and 404 of the routine shown in FIG. By executing the processing of step 105 in the routine shown in FIG. 11, the state detecting means described in the claims can execute the processing of step 105 in the routine shown in FIG. By executing the routine shown in FIG. 24, the remote operation start means described in the claims can They are respectively realized.

In the first to ninth embodiments, the temperature of the heater 68 is determined based on the heater resistance R, and this temperature is used as the sensor temperature T. It is not limited. For example, the sensor element 66 increases as the sensor temperature T increases.
It has the characteristic that impedance becomes low. Therefore, an AC voltage of a predetermined frequency is applied to the sensor element 66,
The sensor temperature T may be obtained by 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.

In the above embodiment, the sensor current I continuously changes according to the air-fuel ratio.
Although the present invention is not limited to this, the present invention is not limited to this, and instead of one or both of the air-fuel ratio sensors 62 and 64, O that outputs a two-stage signal of rich / lean according to the air-fuel ratio is output. _Two sensors may be used. Further, in the above 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.

[0113]

As described above, according to the first to third aspects of the present invention, when the driver has no intention to start the internal combustion engine, the battery is prevented from being discharged by prohibiting or stopping the preheating. Can be. Claims 4 and 5
According to the invention described above, by controlling the amount of energization in preheating in accordance with the state of the battery, it is possible to prevent excessive discharge of the battery due to preheating.

According to the sixth aspect of the present invention, by controlling the amount of power supplied during preheating in accordance with the state of the battery and the power consumption of the starter, it is possible to ensure good startability of the internal combustion engine. Further, according to the inventions described in claims 7 to 9, by controlling the energization state in the preheating according to the power consumption of the starter, the discharge of the battery is prevented from being discharged, and the good startability of the internal combustion engine is ensured. can do.

According to the tenth to twelfth aspects of the present invention, the discharge of the battery can be suppressed by prohibiting the preheating when the execution of the preheating is unnecessary. Furthermore, according to the thirteenth aspect, when the starting operation is performed by the remote starting means, the discharge of the battery can be suppressed.

[Brief description of the drawings]

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 the present invention is applied.

FIG. 2 is a diagram showing 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.

FIG. 3 is a flowchart of a routine executed by an ECU to permit preheating in the first embodiment of the present invention.

FIG. 4 is a diagram showing an example of EC to perform preheating in the present embodiment.
6 is a flowchart of a routine executed by U.

FIG. 5 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. 6 is a diagram showing sensors and the like connected to an ECU in a second embodiment of the present invention.

FIG. 7 is a diagram showing a relationship between a battery specific gravity BS and a starting time Te.

FIG. 8 is a diagram showing an example in which E is used to permit preheating in this embodiment.
It is a flowchart of the routine which CU performs.

FIG. 9 is a flowchart of a routine executed by the ECU to perform a second condition determination for permitting preheating in the third embodiment of the present invention.

FIG. 10 is a diagram showing an example in which E is performed to perform preheating in the present embodiment.
It is a flowchart of the routine which CU performs.

FIG. 11 is a flowchart of a routine executed by the ECU to perform preheating and to stop preheating when a predetermined condition is satisfied in the fourth embodiment of the present invention.

FIG. 12 is a flowchart of a routine executed by an ECU to permit preheating in a fifth embodiment of the present invention.

FIG. 13 is a map referred to for determining the energizing time δ in preheating from the battery specific gravity BS and the battery liquid temperature BTH in the present embodiment.

FIG. 14 is a flowchart of a routine executed by an ECU to permit preheating in a sixth embodiment of the present invention.

FIG. 15 is a flowchart of a routine executed by an ECU to prohibit preheating in the present embodiment.

FIG. 16 is a map that is referred to in this embodiment to determine the required charging amount Ws for cranking from the water temperature THW.

FIG. 17 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.

FIG. 18 is a diagram showing an example in which E is used to permit preheating in this embodiment.
It is a flowchart of the routine which CU performs.

FIG. 19 is a diagram showing an example of E to prevent preheating in this embodiment.
It is a flowchart of the routine which CU performs.

FIG. 20 is a flowchart of a routine executed by an ECU to permit preheating in an eighth embodiment of the present invention.

FIG. 21 is a diagram showing E in order to prohibit preheating in this embodiment.
It is a flowchart of the routine which CU performs.

FIG. 22 is a diagram showing a connection relationship between an ECU and a remote start system according to a ninth embodiment of the present invention.

FIG. 23 is a flowchart of a routine executed by the ECU to permit preheating in the ninth embodiment of the present invention.

FIG. 24 is a flowchart of a routine executed by the ECU to start the internal combustion engine after the remote start operation in the present embodiment.

[Explanation of symbols]

 Reference Signs List 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

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Koji Ide 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 2G004 BJ01 BL08 BL20 3G301 JA00 JA02 JA21 JB01 JB09 KA01 LC10 NA08 NB11 ND01 ND41 NE01 NE23 PD05A PD05B PD05Z PD13B PD13Z PE01Z PE08Z PF01Z PF16Z PG01Z PG02Z

Claims (13)

[Claims] 1. A heater control device for controlling energization of a heater provided in an air-fuel ratio sensor provided in an internal combustion engine, comprising: preheating means for energizing the heater before starting the internal combustion engine; Starting intention judging means for judging the presence / absence of the starting intention, and energizing control means for controlling the energization state of the heater by the preheating means based on the judgment result by the starting intention judging means. Control device for an air-fuel ratio sensor for an internal combustion engine. 2. The heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 1, wherein the energization control unit energizes the heater by the preheating unit when it is determined that there is no intention to start. A heater control device for an air-fuel ratio sensor for an internal combustion engine, which is stopped or prohibited. 3. The heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 1, wherein the energization control means determines that the starting intention is present when it is determined that there is no starting intention. than,
A heater control device for an air-fuel ratio sensor for an internal combustion engine, wherein an amount of electricity supplied to said heater by said preheating means is reduced. 4. A heater control device for controlling energization of a heater provided in an air-fuel ratio sensor provided in an internal combustion engine, comprising: a preheating means for energizing the heater before starting the internal combustion engine; and detecting a state of a battery. A heater control device for an air-fuel ratio sensor for an internal combustion engine, comprising: a battery state detecting unit that performs power supply to the heater based on a state of the battery. . 5. The heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 4, 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. A heater control device for an air-fuel ratio sensor for an internal combustion engine. 6. The heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 4, further comprising: starter power consumption prediction means for predicting power consumption of a starter when the internal combustion engine is started; A heater control device for an air-fuel ratio sensor for an internal combustion engine, wherein an energization state of the heater by the preheating means is controlled based on the predicted power consumption and a state of the battery. 7. A heater control device for controlling energization of a heater included in an air-fuel ratio sensor provided in an internal combustion engine, comprising: preheating means for energizing the heater before starting the internal combustion engine; An internal combustion engine comprising: a starter power prediction unit for predicting power consumption of a starter in the above, and an energization control unit for controlling an energization state of the heater by the preheating unit based on the estimated power consumption. A heater control device for an engine air-fuel ratio sensor. 8. The heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 7, wherein the energization control unit controls the heater by the preheating unit when the predicted power consumption exceeds a predetermined value. A heater control device for an air-fuel ratio sensor for an internal combustion engine, wherein energization is prohibited or stopped. 9. The heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 7, wherein the energization control means includes: when the predicted power consumption exceeds a predetermined value, as compared to when the predicted power consumption does not exceed a predetermined value. A heater control device for an air-fuel ratio sensor for an internal combustion engine, wherein an amount of electricity supplied to said heater by said preheating means is reduced. 10. A heater control device for controlling energization of a heater provided in an air-fuel ratio sensor provided in an internal combustion engine, comprising: preheating means for energizing the heater before starting the internal combustion engine; Preheat unnecessary state detecting means for detecting a predetermined state in which energization to the heater is unnecessary, and, when the predetermined state is detected, preheat inhibition means for inhibiting energization of the heater by the preheating means, A heater control device for an air-fuel ratio sensor for an internal combustion engine, comprising: 11. The air-fuel ratio for an internal combustion engine according to claim 10, wherein the predetermined state is a state in which an abnormality has occurred in the air-fuel ratio sensor. Sensor heater control device. 12. The heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 10, wherein the internal combustion engine is mounted on a vehicle provided with a security system that operates when an intruder into the vehicle is detected. The heater control device for an air-fuel ratio sensor for an internal combustion engine according to claim 10, wherein the predetermined state is a state where the security system is operating. 13. A heater control device for controlling energization of a heater provided in an air-fuel ratio sensor provided in an internal combustion engine, comprising: preheating means for energizing the heater before starting the internal combustion engine; Remote start means for starting the heater, and when a start operation is performed by the remote start means, the preheating means energizes the heater with a smaller amount of electricity than a normal amount of electricity, and then performs internal combustion. A heater control device for an air-fuel ratio sensor for an internal combustion engine, comprising: starting means for remote operation for starting the engine.