Patent Description:
There has been known an automatic stop-start control apparatus for an internal combustion engine, in which when an abnormality occurs in the power supply circuit, sometimes electric power cannot be supplied to an E/G starter motor from a battery, and thus the automatic stop-start control for the engine is not performed (for example, refer to <CIT> (<CIT>)). Document <CIT> discloses that, in a hybrid vehicle, once an engine is started in response to prohibition of an operation stop of the engine based on a deterioration factor, the operation stop of the engine is not allowed irrespective of the value of the deterioration factor D until elapse of a certain time period since the start of the engine. The deterioration factor is computed based on a value of electric current flowing through the accumulator. Document <CIT> discloses a vehicle controlling system including an engine as a power source of a vehicle, an electric storage device, a generator that generates power by rotating in conjunction with a rotation of the engine, a starting device that starts the engine by consuming power from the electric storage device, and a power steering device which can receive power supplied from the electric storage device and the generator, respectively, and operates by consuming the supplied power, wherein the engine is started by the starting device based on a vehicle speed and a predetermined vehicle speed which is a vehicle speed when the engine is started is changed in response to a state of the electric storage device, when an execution of an inertial running in which the engine is stopped to allow the vehicle to run with inertia
Document <CIT> discloses an abnormality detection apparatus for power supply circuit. Document <CIT> discloses a control device for an idling stop vehicle. Document <CIT> discloses an open-circuit voltage deducing device of the battery for the vehicle which includes a voltage-detecting means for detecting the battery voltage, and a current-detecting means to detect a battery current flowing through a load of the vehicle from the battery, wherein the deducing device includes an open-circuit voltage deducing means which deduces the battery voltage detected by the voltage-detecting means to be the open-circuit voltage, in such a state such that the ignition switch of the vehicle is in off state, and in a state where the battery current, detected by the current detecting means, is smaller than a set value has continued for a fixed time interval.

It is useful to initiate idling stop control in a non-stop state of the vehicle by taking account of the state of the battery.

The present invention provides a vehicle control apparatus that is capable of initiating the idling stop control in the non-stop state of the vehicle by taking account of the state of the battery.

According to an aspect of the present invention, there is provided a vehicle control apparatus according to claim <NUM>. Further aspects of the present invention are set out in the dependent claim.

According to the present invention, it is possible to provide a vehicle control apparatus that is capable of initiating the idling stop control in the non-stop state of the vehicle by taking account of the state of the battery.

Features, advantages and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:.

Hereinafter, various embodiments will be described in detail with reference to the accompanying drawings. It is noted that the processing described with respect to <FIG> and <FIG> does not form part of the present invention.

<FIG> is a structural diagram of a power supply system of a vehicle according to an embodiment. As shown in <FIG>, the present embodiment is suitable to be mounted in vehicles equipped only with an engine (that is, vehicles other than a hybrid vehicle or an electrical vehicle). In the structure shown in <FIG>, an alternator <NUM> is mechanically connected with an engine <NUM>. The alternator <NUM> is an electric generator for generating electric power by using the power from the engine <NUM>. The electric power generated by the alternator <NUM> is used to charge a battery <NUM> and/or to drive vehicle loads <NUM>. In addition, the battery <NUM> is provided with a current sensor <NUM>. The current sensor <NUM> detects the battery current (the charge current and/or discharge current of the battery <NUM>). The battery <NUM> is typically a lead battery, and may also be other kinds of batteries (or capacitors). A voltage sensor <NUM> is provided in the battery <NUM>. The vehicle loads <NUM> may be any kinds of loads, for example, a starter <NUM>, an air conditioning device, wipers, and so on. In such a structure, the state of charge (SOC) of the battery <NUM> can be controlled by controlling the power generation voltage of the alternator <NUM>.

However, the present embodiment may also be applied to a dual-power supply structure. For example, the present embodiment can also be applied to a structure obtained by arranging a second battery in parallel with the battery <NUM> in the structure shown in <FIG>. In this case, the starter <NUM> can be powered not only from the battery <NUM>, but also from the second battery.

In addition, hereinafter, description will be further given by way of example on the premise of the structure shown in <FIG>.

<FIG> are diagrams showing exemplary structures associated with a brake booster. <FIG> shows a structure for generating a negative pressure by using the intake negative pressure of the engine <NUM>, and <FIG> shows a structure for generating a negative pressure by using the driving of an actuator <NUM>, wherein the brake booster <NUM> is a device for assisting the user's brake operation by means of the negative pressure. The brake booster <NUM> can be of any kind of specific structure, and the negative pressure can also be generated by any kind of method. For example, the negative pressure in the brake booster <NUM> can either be generated by using the intake negative pressure of the engine <NUM> as shown in <FIG>, or be generated by driving the actuator <NUM>, such as a vacuum pump, as shown in <FIG>. In addition, the brake booster <NUM> is not limited to the vacuum type, and may be compressed air type by using compressed air from a compressor (am example of the actuator <NUM>), or hydraulic pressure type by using a hydraulic pressure pump (an example of the actuator <NUM>). In the example shown in <FIG>, the negative pressure in the brake booster <NUM> can also be generated while the engine <NUM> is stopped. The actuator <NUM> is included in the vehicle loads <NUM> shown in <FIG>, and is operated by the electric power from the battery <NUM>.

<FIG> is a systematic structural diagram showing a control system according to an embodiment.

The control system <NUM> includes a processing device <NUM>. The processing device <NUM> can be constructed by an operation processing device including a CPU. Various functions (including the functions described later) of the processing device <NUM> can be implemented by any hardware, software, firmware, or the combination thereof. For example, any part or all of the functions of the processing device <NUM> can be implemented by an ASIC (application-specific integrated circuit), a FPGA (Field Programmable Gate Array), or a DSP (Digital Signal Processor), that is directed to a specific application. In addition, the processing device <NUM> may also be implemented by a plurality of processing devices (including the processing device in the sensor).

The processing device <NUM> includes an abnormality detection part <NUM>, a control suppression part <NUM>, and an S&S control part <NUM>. In addition, S&S is an abbreviation of Stop & Start.

The S&S control part <NUM> is connected with a vehicle speed sensor <NUM> and a pressure sensor <NUM> for detecting the negative pressure in the brake booster <NUM> (hereinafter referred to as "booster negative pressure"). In addition, various information required for determination of predetermined idling stop initiation conditions described later (e.g., information related to internal air temperature, operation amount of a brake pedal, etc.) or the like, can be input to the S&S control part <NUM>. The S&S control part <NUM> is connected with the control suppression part <NUM>. The control suppression part <NUM> is connected with the abnormality detection part <NUM>, and the abnormality detection part <NUM> is connected with the current sensor <NUM>.

In addition, the abnormality detection part <NUM>, the control suppression part <NUM> and the S&S control part <NUM> can be implemented as ECUs (electronic control unit), respectively. Alternatively, the abnormality detection part <NUM> and the control suppression part <NUM> may be implemented by a single ECU, while the S&S control part <NUM> may be implemented by another ECU. For example, the S&S control part <NUM> may be implemented by an idling stop control ECU other than the engine ECU for controlling the engine. In addition, in this case, the various ECUs may be connected in any manner. For example, the connection may be achieved via a bus such as CAN (controller area network), may be indirect connection via other ECU(s) etc., may be direct connection, or may be achieved by wireless communication.

The abnormality detection part <NUM> detects the abnormal state of the battery <NUM>. The abnormal state of the detected object is, for example, an abnormal state in which the engine <NUM> cannot be started by the starter <NUM>. Hereinafter, as an example, the open circuit fault state of the battery <NUM> is provided as the abnormal state of the detected object. The open circuit fault of the battery <NUM> occurs due to an open circuit fault occurred inside the battery <NUM>, or disengagement of terminals (wiring terminals) of the battery <NUM>. The open circuit fault inside the battery <NUM> may occur due to internal mechanical damage (the pole is broken off, welding parts between the battery cells are broken, or the like), invasion of corrosive substances, evaporation of electrolyte solution, degradation over time, etc. In addition, when an open circuit fault occurs in the battery <NUM>, current does not flow into the battery <NUM> any longer, and thus the battery current detected by the current sensor <NUM> becomes almost <NUM>.

There are various kinds of methods for detecting the open circuit fault of the battery <NUM>, and any method may be used. For example, the open circuit fault of the battery <NUM> can be detected by using the method described in <CIT> (<CIT>). Preferred embodiments of the method for detecting the open circuit fault of the battery <NUM> will be described later.

The control suppression part <NUM> suppresses the control of the S&S control part <NUM> based on the detection result of the abnormality detection part <NUM>, and so on. This will be described later.

The S&S control part <NUM> determines whether predetermined idling stop initiation conditions are satisfied or not based on the vehicle speed information from the vehicle speed sensor <NUM>, and so on, and if it is determined that the predetermined idling stop initiation conditions are satisfied, the engine is stopped to initiate the idling stop control. Hereinafter, for the sake of convenience, the idling stop control performed in the vehicle stop state will be referred to as "stop S&S". In addition, the initiation conditions for the stop S&S will be referred to as "stop S&S initiation conditions". The stop S&S initiation conditions include the vehicle speed being <NUM>. Other conditions included by the stop S&S initiation conditions may be any conditions, for example, may include the open circuit fault of the battery <NUM> being not detected based on the voltage sensor <NUM>, the brake pedal being depressed, the negative pressure of the booster being at or above a predetermined value, and conditions related to the air conditioner state, the SOC of the battery <NUM>, the road slope, etc..

The S&S control part <NUM> also initiates the idling stop control in the vehicle deceleration state. Hereinafter, the idling stop control performed in the vehicle deceleration state will be referred to as "deceleration S&S". In addition, the initiation conditions for the deceleration S&S will be referred to as "deceleration S&S initiation conditions". The deceleration S&S initiation conditions include the vehicle speed being at or below a predetermined vehicle speed Vth (hereinafter referred to as "E/G stop vehicle speed Vth"). The E/G stop vehicle speed Vth can be a value within a low vehicle speed range, such as around <NUM>/h, and can also be set variable as described later. Other conditions included by the deceleration S&S initiation conditions may be any conditions, for example, may include the open circuit fault of the battery <NUM> being not detected based on the voltage sensor <NUM>, the brake pedal being depressed, the negative pressure of the booster being at or above a predetermined value, and conditions related to the air conditioner state, the SOC of the battery <NUM>, the road slope, etc..

<FIG> are flowcharts showing an example of the S&S initiation processing performed by the S&S control part <NUM>, wherein <FIG> shows processing related to the deceleration S&S, and <FIG> shows processing related to the stop S&S. The processing routines shown in <FIG> are repeatedly performed in parallel, respectively, at a predetermined processing cycle time e.g. during the operation of the engine <NUM>.

Referring to <FIG>, in step <NUM>, it is determined whether or not a deceleration S&S prohibition flag is set. The deceleration S&S prohibition flag is sometimes set by the control suppression part <NUM>. The deceleration S&S prohibition flag will be described in detail later. In the case where the deceleration S&S prohibition flag has been set, the processing returns to step <NUM>, otherwise proceeds to step <NUM>.

In step <NUM>, based on the information from the vehicle speed sensor <NUM>, it is determined whether or not the vehicle speed is at or below the E/G stop vehicle speed Vth. In the case where the vehicle speed is at or below the E/G stop vehicle speed Vth, the processing proceeds to step <NUM>, otherwise returns to step <NUM>.

In step <NUM>, it is determined whether or not other deceleration S&S initiation conditions are satisfied. As mentioned above, other deceleration S&S initiation conditions may include the open circuit fault of the battery <NUM> being not detected based on the voltage sensor <NUM>, the brake pedal being depressed, etc. In the case where other deceleration S&S initiation conditions are satisfied, the processing proceeds to step <NUM>, otherwise returns to step <NUM>.

In step <NUM>, the deceleration S&S is initiated. That is, the engine <NUM> is stopped.

In addition, in <FIG>, the processing sequence of step <NUM>, step <NUM>, and step <NUM> may be arbitrarily set. For example, the determination in step <NUM> may also be performed preceding the determination in step <NUM>.

Referring to <FIG>, in step <NUM>, based on the information from the vehicle speed sensor <NUM>, it is determined whether or not the vehicle speed is <NUM>. In the case where the vehicle speed is <NUM>, the processing proceeds to step <NUM>, otherwise returns to step <NUM>.

In step <NUM>, it is determined whether or not other stop S&S initiation conditions are satisfied. As mentioned above, other stop S&S initiation conditions may include the open circuit fault of the battery <NUM> being not detected based on the voltage sensor <NUM>, the brake pedal being depressed, etc. In the case where other stop S&S initiation conditions are satisfied, the processing proceeds to step <NUM>, otherwise returns to step <NUM>. In addition, the determination on other stop S&S initiation conditions may not be repeatedly performed. That is, in the case where the determination in step <NUM> is NO, the processing may be ended there (in this case, for the situation where the vehicle speed is <NUM> this time, the stop S&S is not initiated). Alternatively, the determination on other stop S&S initiation conditions may be repeatedly performed for predetermined times or predetermined period of time.

In step <NUM>, the stop S&S is initiated. That is, the engine <NUM> is stopped.

In addition, in <FIG>, the processing sequence of step <NUM> and step <NUM> may be arbitrarily set. For example, the determination in step <NUM> may also be performed preceding the determination in step <NUM>.

<FIG> is a flowchart showing another example of the S&S initiation processing performed by the S&S control part <NUM>. The processing shown in <FIG> is suitable to be performed in a structure in which the deceleration S&S prohibition flag is not used and the deceleration S&S and stop S&S are collectively performed (e.g. refer to <FIG>, <FIG> and <FIG> described later). Here, as a premise, in the deceleration S&S initiation conditions and the stop S&S initiation conditions, conditions other than the vehicle speed are set to be identical, and are simply referred to as "S&S initiation conditions". In addition, in the deceleration S&S initiation conditions and the stop S&S initiation conditions, conditions other than the vehicle speed may also be different, and in this case, the determination processing is differently performed in accordance with the vehicle speed. The processing routine shown in <FIG> may be repeatedly performed at a predetermined processing cycle time e.g. during the operation of the engine <NUM>.

In step <NUM>, based on the information from the vehicle speed sensor <NUM>, it is determined whether or not the vehicle speed is at or below the E/G stop vehicle speed Vth. If the vehicle speed is at or below the E/G stop vehicle speed Vth, the processing proceeds to step <NUM>, otherwise returns to step <NUM>.

In step <NUM>, it is determined whether or not other S&S initiation conditions are satisfied. As mentioned above, other S&S initiation conditions may include the open circuit fault of the battery <NUM> being not detected based on the voltage sensor <NUM>, the brake pedal being depressed, etc. If the other S&S initiation conditions are satisfied, the processing proceeds to step <NUM>, otherwise returns to step <NUM>.

In step <NUM>, the deceleration S&S or the stop S&S is initiated. That is, the engine <NUM> is stopped. In addition, at this time, if the vehicle speed is <NUM>, the stop S&S is initiated, and if the vehicle speed is larger than <NUM>, the deceleration S&S is initiated.

<FIG> is a flowchart showing an example of S&S termination processing performed by the S&S control part <NUM>. The processing shown in <FIG> is repeatedly performed at a predetermined processing cycle time, for example, during the idling stop control following initiation of the deceleration S&S or the stop S&S.

In step <NUM>, it is determined whether or not predetermined idling stop termination conditions are satisfied. The predetermined idling stop termination conditions are arbitrary, and may typically include, for example, the depression of the brake pedal being released, the negative pressure of the booster becoming lower than a predetermined value, and conditions related to the air conditioner state (degradation of the comfortability of the air conditioner), the battery state (decrease of the amount of charge), etc. In the case where the predetermined idling stop termination conditions are satisfied, the processing proceeds to step <NUM>, otherwise returns to step <NUM>.

In step <NUM>, the engine <NUM> is restarted to terminate the idling stop control.

<FIG> is a flowchart showing an example of processing performed by the abnormality detection part <NUM> and the control suppression part <NUM>. The processing routine shown in <FIG> is initiated, for example, upon turning-on of the ignition switch of the vehicle, and then is repeatedly performed at a predetermined processing cycle time, until the ignition switch is turned off. However, the processing in step <NUM> (and the processing in step <NUM> following it) is only performed during travel of the vehicle. The processing shown in <FIG> is suitable to be performed in the case where the processing shown in <FIG> is performed by the S&S control part <NUM>.

In step <NUM>, the abnormality detection part <NUM> determines whether or not an open circuit fault occurs in the battery <NUM>. Specifically, based on the detected value of the current sensor <NUM>, it is determined whether or not the state where the current of the battery is within a predetermined range ΔA1 (in this example, ≥ -<NUM> [A] and ≤ <NUM> [A]) has continued for a predetermined time ΔT1. The predetermined range ΔA1 corresponds to the range of the detected value of the current sensor <NUM> obtainable in the case where the open circuit fault occurs in the battery <NUM>, and can be suitably determined by experiments, etc. Typically, the predetermined range ΔA1 is a range centered at <NUM> [A], and is set in consideration of the offset of the current sensor <NUM>. That is, there is possibly an initial offset (or an offset generated over time) in the current sensor <NUM>, and even in the case where the current is actually <NUM> [A], sometimes a slight current value (for example, <NUM> [A]) will be displayed. The predetermined time ΔT1 is set by considering the fact that the current of the battery sometimes falls within the predetermined range ΔA1 even if no open circuit fault occurs in the battery <NUM>. For example, in the case where noise is generated, in the case the vehicle loads <NUM> are not operated, the current of the battery may fall within the predetermined range ΔA1. The predetermined time ΔT1 may be, for example, <NUM> [s].

Here, it is preferred that the predetermined range ΔA1 is set to be relatively wide, and in addition, the predetermined time ΔT1 is set to be relatively short. The wider the predetermined range ΔA1 is, the higher the possibility of misdetection (being determined as open circuit fault though in normal) is, and the shorter the predetermined time ΔT1 is, the higher the possibility of the misdetection is. Therefore, when the predetermined range ΔA1 is set to be relatively wide and the predetermined time ΔT1 is set to be relatively short, the possibility of misdetection becomes higher. On the other hand, however, the wider the predetermined range ΔA1 is, the lower the possibility of the situation where the open circuit fault cannot be detected though it has actually occurred in the battery <NUM> (failure in detecting the open circuit fault) is (that is, the higher the detection sensitivity for the open circuit fault is), and the shorter the predetermined time ΔT1 is, the lower the possibility that the open circuit fault detection fails is, and it is possible to detect the open circuit fault earlier. In this regard, in the case of misdetection, as described later, the deceleration S&S is prohibited, and the opportunity to improve the fuel economy will be lost; while in the case of detection failure, a situation where after the engine is stopped following initiation of the deceleration S&S, the engine <NUM> cannot be started even if the negative pressure of the booster becomes insufficient may occur. Therefore, the predetermined range ΔA1 and/or the predetermined time ΔT1 are/is set preferably from the standpoint that avoiding the situation where the engine <NUM> cannot be started has priority over the deceleration S&S, so that the sensitivity for detecting the open circuit fault becomes high. In other words, the predetermined range ΔA1 and/or the predetermined time ΔT1 are/is set to have a high sensitivity from the standpoint that achievement of safety by ensuring the negative pressure of the booster has priority over improvement of fuel economy by the deceleration S&S.

In step <NUM>, if it is determined that the state where the current of the battery is in the predetermined range ΔA1 has continued for the predetermined time ΔT1, it is determined that the battery <NUM> is in the open circuit fault state, and the processing proceeds to step <NUM>. Otherwise, it is determined that no open circuit fault occurs in the battery <NUM>, and the processing in step <NUM> will be performed again in the next processing cycle. In addition, in step <NUM>, whether or not it has continued for the predetermined time ΔT1 may be determined by considering influence of noise. For example, it may be configured such that within a certain processing cycle time, in the case where the current of the battery is within the predetermined range ΔA1, a count value is incremented by <NUM>, and in the case where the current of the battery is not within the predetermined range ΔA1, the count value is decremented by <NUM>. In this case, the count value × the processing cycle time may be set as the time duration in which the current of the battery is within the predetermined range ΔA1, and it is determined whether or not the count value × the processing cycle time is equal to or above the predetermined time ΔT1.

In step <NUM>, the control suppression part <NUM> sets the deceleration S&S prohibition flag. That is, the deceleration S&S prohibition flag is established. When the deceleration S&S prohibition flag is set, the deceleration S&S is prohibited. However, even in the case where the deceleration S&S prohibition flag is set, the stop S&S is still in a state where it can be initiated. That is, even in the case where the deceleration S&S prohibition flag is set, if the stop S&S initiation conditions are satisfied, the stop S&S will be initiated.

In step <NUM>, the control suppression part <NUM> determines whether or not the engine <NUM> has been stopped by the stop S&S. Whether or not the engine <NUM> has been stopped by the stop S&S can be determined on the basis of the information obtained from the S&S control part <NUM>. If it is determined that the engine <NUM> has been stopped by the stop S&S, the processing proceeds to step <NUM>, otherwise it becomes a state to wait for stop of the engine by the stop S&S.

In step <NUM>, the control suppression part <NUM> determines whether or not the engine <NUM> has been restarted following termination of the stop S&S. Whether or not the engine <NUM> has been restarted can be determined on the basis of the information obtained from the S&S control part <NUM>. If it is determined that the engine <NUM> has been restarted, the processing proceeds to step <NUM>, otherwise it becomes a state to wait for restart of the engine.

In step <NUM>, the control suppression part <NUM> resets the deceleration S&S prohibition flag set in the above step <NUM>. That is, the deceleration S&S prohibition flag is cleared. Thus, if thereafter the deceleration S&S initiation conditions are satisfied, the deceleration S&S is initiated.

Here, when the determination in the above step <NUM> is YES, it means that an open circuit fault in the battery <NUM> is detected. When an open circuit fault occurs in the battery <NUM>, the starter <NUM> cannot be operated, and thus the engine <NUM> cannot be restarted. Nevertheless, if the determination in the above step <NUM> is YES, it means that the detection of open circuit fault of the battery <NUM> in the above step <NUM> is incorrect (that is, misdetection). Therefore, in step <NUM>, the deceleration S&S prohibition flag is reset.

According to the processing shown in <FIG>, as described above, in the case where an open circuit fault in the battery <NUM> is detected, the deceleration S&S is prohibited. Thus, the situation where the deceleration S&S is initiated when the open circuit fault occurs in the battery <NUM> can be reduced. If the deceleration S&S is initiated when the open circuit fault occurs in the battery <NUM>, even if the negative pressure of the booster is insufficient due to for example the driver's pump operation of the brake pedal during the deceleration S&S, the engine <NUM> cannot be restarted, and the negative pressure of the booster cannot be ensured. In addition, this situation is not limited to the brake booster <NUM> which uses the intake negative pressure of the engine <NUM> to generate the negative pressure of the booster, and may occur in the case of other kinds of brake booster <NUM>. This is because, when there is an open circuit fault in the battery <NUM>, the actuator <NUM> operated by the electric power of the battery <NUM> cannot be operated. According to the processing shown in <FIG>, it is possible to reduce the situation where the negative pressure of the booster cannot be ensured, and to improve safety.

In addition, according to the processing shown in <FIG>, as described above, even in the case where the open circuit fault of the battery <NUM> is detected, the stop S&S is permitted. Thus, it is possible to prevent the situation where the stop S&S is not performed any longer due to misdetection of the open circuit fault of the battery <NUM>, and to ensure marketability with respect to the misdetection. That is, it is possible to reduce the situation where the opportunity for improving fuel economy is lost due to the misdetection of the open circuit fault of the battery <NUM>. In addition, in the case where the open circuit fault of the battery <NUM> is not misdetected, if the stop S&S is initiated, there will be the situation where the engine <NUM> cannot be restarted even if the negative pressure of the booster is insufficient thereafter. This situation is undesirable; however, since it is in a state where the vehicle speed is <NUM>, the brake force required for maintaining the stop state is low, and it is possible to ensure the required safety. In addition, in the processing shown in <FIG>, as described above, the method for detecting the open circuit fault of the battery <NUM> (the predetermined range ΔA1 and/or predetermined time ΔT1) tends to give priority to the safety so that misdetection easily occurs, thus it can be contemplated that this situation rarely occurs. Thus, according to the processing shown in <FIG>, it is possible to not only ensure the negative pressure of the booster, but also achieve the improvement of fuel economy.

In addition, according the processing shown in <FIG>, as described above, the open circuit fault of the battery <NUM> is detected if the state where the current of the battery is within the predetermined range ΔA1 has continued for the predetermined time ΔT1. This method for detecting the open circuit fault of the battery <NUM> is especially suitable for detecting the open circuit fault of the battery <NUM> during travel of the vehicle. Although there are methods for detecting the open circuit fault of the battery <NUM> based on the voltage of the battery <NUM>, such methods are not suitable for detecting the open circuit fault of the battery <NUM> during travel of the vehicle. This is because during travel of the vehicle, the alternator <NUM> is operated (that is, in the power generation state), thus sometimes, a significant voltage drop of the battery <NUM> cannot be detected even when an open circuit fault occurs in the battery <NUM>. Thus, according to the processing shown in <FIG>, it is possible to detect the open circuit fault of the battery <NUM> during travel of the vehicle. In addition, as described above, since it is configured to prohibit the deceleration S&S following detection of the open circuit fault of the battery <NUM>, the open circuit fault of the battery <NUM> needs to be detected during travel of the vehicle. This is because the deceleration S&S is a control initiated in the vehicle travel state.

In addition, according to the processing shown in <FIG>, as described above, even in the case where the deceleration S&S prohibition flag is set, when the engine has been restarted (that is, when the engine is successfully restarted), the deceleration S&S prohibition flag is reset. That is, the engine having been restarted means misdetection of the open circuit fault of the battery <NUM>, so the deceleration S&S prohibition flag is reset. Therefore, as long as thereafter no open circuit fault of the battery <NUM> is detected again, it becomes a state where the deceleration S&S can be initiated. Thus, according to the processing shown in <FIG>, it is possible to prevent the deceleration S&S prohibition state from being continuously maintained due to misdetection of the open circuit fault of the battery <NUM>.

In addition, in the processing shown in <FIG>, as described above, in the case where the engine has been restarted in step <NUM> (that is, in the case where the engine is successfully restarted), the deceleration S&S prohibition flag is reset. However, it may also be configured such that after the engine <NUM> has been stopped by the stop S&S, in the case where a battery current at or above a predetermined value (e.g., significantly larger than the battery current within the predetermined range ΔA1 used in the above step <NUM>) is detected based on the detected signal of the current sensor <NUM> and/or in the case where a predetermined vehicle load <NUM> is normally operated, etc., the deceleration S&S prohibition flag is reset.

In addition, in the processing shown in <FIG>, as described above, in the above step <NUM>, a simple method for detecting the open circuit fault of the battery <NUM> only based on the current of the battery is provided. However, as described above, other deceleration S&S initiation conditions include the open circuit fault of the battery <NUM> being not detected based on the voltage sensor <NUM>. Thus, it is actually such that, during travel of the vehicle, whether or not an open circuit fault occurs in the battery <NUM> is independently determined based on the voltage sensor <NUM> and the current sensor <NUM>, respectively. However, other deceleration S&S initiation conditions may also not include the open circuit fault of the battery <NUM> being not detected based on the voltage sensor <NUM>. This is because, as described above, during travel of the vehicle, the alternator <NUM> is operated, thus sometimes, a significant voltage drop of the battery <NUM> may not be detected even when the open circuit fault occurs in the battery <NUM>. In addition, during stop of the vehicle, the open circuit fault of the battery <NUM> is determined based on the voltage sensor <NUM> rather than the current sensor <NUM>.

In addition, in the processing shown in <FIG>, as described above, in the case where the open circuit fault of the battery <NUM> is detected, the deceleration S&S is prohibited by setting the deceleration S&S prohibition flag; however, it is also possible that in the case where the open circuit fault of the battery <NUM> is detected, other conditions included by the deceleration S&S initiation conditions are varied to achieve essentially the same configuration. For example, in the case where the open circuit fault of the battery <NUM> is detected, the deceleration S&S may also be prohibited by increasing a threshold for the negative pressure of the booster to infinite, etc..

<FIG> is a flowchart showing another example of processing performed by the abnormality detection part <NUM> and the control suppression part <NUM>. The processing routine shown in <FIG> is initiated, for example, upon turning-on of the ignition switch of the vehicle, and then is repeatedly performed at a predetermined processing cycle time, until the ignition switch is turned off. However, the processing in step <NUM> to step <NUM> is only performed during travel of the vehicle. The processing shown in <FIG> is suitable for the situation where the S&S control part <NUM> performs the processing shown in <FIG>.

The processing shown in <FIG> differs from that shown in <FIG> mainly in the addition of step <NUM>. The processing in step <NUM>, step <NUM>, step <NUM> and step <NUM> may be the same as the processing in step <NUM>, step <NUM>, step <NUM> and step <NUM> shown in <FIG>. Hereinafter, the processing unique to <FIG> will be described.

In step <NUM> performed following step <NUM>, the abnormality detection part <NUM> determines again whether or not an open circuit fault occurs in the battery <NUM>. Specifically, it is determined whether or not the state where the current of the battery is within a predetermined range ΔA2 (in this example, < -<NUM> [A] or > <NUM> [A]) has continued for a predetermined time ΔT2 based on the detected value of the current sensor <NUM>. The predetermined range ΔA2 is set to exclude the range of the detected value of the current sensor <NUM> obtainable in the case where the open circuit fault occurs in the battery <NUM>, and can be determined by experiments, etc. The predetermined range ΔA2 is a range excluding the predetermined range ΔA1 used in step <NUM>. In this example, the predetermined range ΔA2 is lower than -<NUM> [A] or larger than <NUM> [A], and is a range which is not provided with margin with respect to the predetermined range ΔA1 (in this example, ≥ -<NUM> [A] and ≤ <NUM> [A]). However, for example, the predetermined range ΔA2 may also be provided with margin with respect to the predetermined range ΔA1, such as being lower than -<NUM> [A] or larger than <NUM> [A]. In addition, the margin may be set, like the determination condition in step <NUM>, to be relatively large from the standpoint that avoiding the situation where the engine <NUM> cannot be started has priority over the deceleration S&S. The predetermined time ΔT2 may be set from the same standpoint as the predetermined time ΔT1 used in step <NUM>, and may be for example <NUM> [s].

In addition, in step <NUM>, whether or not it has continued for the predetermined time ΔT2 may be determined by considering influence of noise. For example, it can be configured such that within a certain processing cycle time, in the case where the current of the battery is within the predetermined range ΔA2, a count value is incremented by <NUM>, and in the case where the current of the battery is not within the predetermined range ΔA2, the count value is decremented by <NUM>. In this case, the count value × the processing cycle time may be set as the time duration in which the current of the battery is within the predetermined range ΔA2, and it is determined whether or not the count value × the processing cycle time is equal to or above the predetermined time ΔT2.

In step <NUM>, if it is determined that the state where the current of the battery is within the predetermined range ΔA2 has continued for the predetermined time ΔT2, the processing proceeds to step <NUM>, otherwise proceeds to step <NUM>. Therefore, in the processing shown in <FIG>, even if it is not determined to be YES in step <NUM>, when it is determined that the state where the current of the battery is within the predetermined range ΔA2 has continued for the predetermined time ΔT2, the deceleration S&S prohibition flag is also reset.

In step <NUM>, the control suppression part <NUM> determines whether or not the engine <NUM> has been stopped by the stop S&S. Whether or not the engine <NUM> has been stopped by the stop S&S can be determined on the basis of the information obtained from the S&S control part <NUM>. If it is determined that the engine <NUM> has been stopped by the stop S&S, the processing proceeds to step <NUM>, otherwise returns to step <NUM>.

According to the processing shown in <FIG>, the same effects can be achieved as the processing shown in <FIG>. In addition, according to the processing shown in <FIG>, even if there is temporarily a positive determination in step <NUM> such that the deceleration S&S prohibition flag is set, before the stop S&S is initiated thereafter, it is possible to reset the deceleration S&S prohibition flag according to the determination result in step <NUM>. That is, even in the case where the open circuit fault of the battery <NUM> is temporarily detected in step <NUM> such that the deceleration S&S prohibition flag is set, thereafter whether or not the open circuit fault occurs in the battery <NUM> will be confirmed again. Thus, even in the case where the open circuit fault of the battery <NUM> is misdetected in step <NUM>, it is possible to reset the deceleration S&S prohibition flag by the redetermination thereafter. As a result, it is possible to reduce the situation where the opportunity for improving fuel economy is lost due to misdetection of the open circuit fault of the battery <NUM>.

In addition, in the processing shown in <FIG>, in the case where the open circuit fault of the battery <NUM> is temporarily detected in step <NUM> such that the deceleration S&S prohibition flag is set, the determination in step <NUM> is repeatedly performed at a predetermined processing cycle time, until the engine <NUM> is stopped by the stop S&S. However, the determination in step <NUM> may be performed, before the engine <NUM> is stopped by the stop S&S, only once, or may be performed predetermined times no less than twice. In addition, the determination in step <NUM> may be performed, before the engine <NUM> is stopped by the stop S&S, every predetermined period of time (>> the predetermined processing cycle time) has elapsed, and may also be performed upon every predetermined travel distance.

<FIG> is a flowchart showing another example of processing performed by the abnormality detection part <NUM> and the control suppression part <NUM>. The processing routine shown in <FIG> is initiated, for example, upon turning-on of the ignition switch of the vehicle, and then is repeatedly performed at a predetermined processing cycle time, until the ignition switch is turned off. The processing shown in <FIG> is suitable for the situation where the S&S control part <NUM> performs the processing shown in <FIG>.

In the processing as shown in <FIG>, as a premise, it is configured such that the voltage sensor <NUM> and the current sensor <NUM> are formed by a sensor obtained by integrated assembly of the sensors with a processing unit (e.g. microprocessor) (hereinafter, for the sake of simplicity, referred to as "smart battery sensor"). The smart battery sensor is also equipped with a temperature sensor therein. Hereinafter, as a premise, it is configured such that the processing unit inside the smart battery sensor has a function to detect the open circuit fault of the battery <NUM> such as the disengagement of battery terminals, and if it is detected that an open circuit fault occurs in the battery <NUM>, a battery broken information is sent to the S&S control part <NUM>.

The processing shown in <FIG> differs from that shown in <FIG> mainly in the processing in step <NUM>. The processing in step <NUM> to step <NUM> shown in <FIG> may be the same as the processing in step <NUM> to step <NUM> shown in <FIG>. Hereinafter, the processing unique to <FIG> will be described.

In step <NUM>, the abnormality detection part <NUM> determines whether or not the battery broken information is received from the smart battery sensor. If the battery broken information is received from the smart battery sensor, it is determined that the battery <NUM> is in open circuit fault state, and the processing proceeds to step <NUM>. Otherwise, it is determined that the battery <NUM> is not in the open circuit fault state, and the processing in step <NUM> will performed again in the next processing cycle.

According to the processing shown in <FIG>, the same effects can be achieved as the processing shown in <FIG>. In addition, the processing shown in <FIG> is especially suitable for the situation where the smart battery sensor has low precision for detecting the open circuit fault. This is because of the standpoint as follows: as described above, avoiding the situation where the engine <NUM> cannot be started has priority over the deceleration S&S.

In addition, in the processing shown in <FIG>, the processing in step <NUM> and step <NUM> may be performed only during travel of the vehicle. This is because when the vehicle is stopped, considering drop of the voltage value, precision of the smart battery sensor for detecting the open circuit fault may become higher.

<FIG> is a flowchart showing another example of processing performed by the abnormality detection part <NUM> and the control suppression part <NUM>. The processing routine shown in <FIG> is initiated, for example, upon turning-on of the ignition switch of the vehicle, and then is repeatedly performed at a predetermined processing cycle time, until the ignition switch is turned off. However, the processing in step <NUM> (and the processing in step <NUM> following it) is performed only during travel of the vehicle.

In the processing shown in <FIG>, as a premise, it is configured such that the deceleration S&S is performed in a deceleration state with a speed at or below the E/G stop vehicle speed Vth. In other words, the deceleration S&S initiation conditions include the deceleration state with a speed at or below the E/G stop vehicle speed Vth. In addition, in the example shown in <FIG>, since the deceleration S&S prohibition flag is not used, the deceleration S&S prohibition flag may be omitted. Therefore, the processing shown in <FIG> is suitable for the situation where the S&S control part <NUM> performs the processing shown in <FIG>.

The processing shown in <FIG> differs from the processing shown in <FIG> mainly in the following aspect: in the case where the open circuit fault of the battery <NUM> is detected, instead of prohibiting the deceleration S&S, the vehicle speed at which the deceleration S&S can be initiated is reduced. The processing in step <NUM> and step <NUM> shown in <FIG> may be the same as the processing in step <NUM> and step <NUM> shown in <FIG>. Hereinafter, the processing unique to <FIG> will be described.

In step <NUM>, the control suppression part <NUM> sets the E/G stop vehicle speed Vth to a predetermined value V1. The initial value of the E/G stop vehicle speed Vth may be a normal value V0. The normal value V0 may be any value including infinite, and for example may be a value within the low vehicle speed range around <NUM>/h. The predetermined value V1 may be any value larger than <NUM> and smaller than the normal value V0. In addition, when the predetermined value V1 is <NUM>, it means that the deceleration S&S is substantially prohibited (only the stop S&S is permitted), thus the processing shown in <FIG> is equivalent to that shown in <FIG>.

In step <NUM>, the control suppression part <NUM> determines whether or not the engine <NUM> has been stopped by the deceleration S&S or the stop S&S. Whether or not the engine <NUM> has been stopped by the deceleration S&S or the stop S&S can be determined on the basis of the information obtained from the S&S control part <NUM>. In the case where it is determined that the engine <NUM> has been stopped by the deceleration S&S or the stop S&S, the processing proceeds to step <NUM>, otherwise it becomes a state to wait for stop of the engine by the deceleration S&S or the stop S&S.

In step <NUM>, the control suppression part <NUM> determines whether or not the engine <NUM> has been restarted following termination of the deceleration S&S or the stop S&S. Whether or not the engine <NUM> has been restarted can be determined on the basis of the information obtained from the S&S control part <NUM>. In the case where it is determined that the engine <NUM> has been restarted, the processing proceeds to step <NUM>, otherwise it becomes a state to wait for restart of the engine.

In step <NUM>, the control suppression part <NUM> sets the E/G stop vehicle speed Vth to the normal value V0. That is, the E/G stop vehicle speed Vth which has been set to the predetermined value V1 in the above step <NUM> is recovered to the normal value V0.

According to the processing shown in <FIG>, as described above, in the case where an open circuit fault of the battery <NUM> is detected, the E/G stop vehicle speed Vth in the deceleration S&S initiation conditions is reduced from the normal value V0 to the predetermined value V1. Thus, when the open circuit fault occurs in the battery <NUM>, it is possible to reduce the situation where the deceleration S&S is initiated in a vehicle speed range higher than the predetermined value V1. If the deceleration S&S is initiated when the open circuit fault occurs in the battery <NUM>, even if the negative pressure of the booster is insufficient due to for example the driver's pump operation of the brake pedal during the deceleration S&S, the engine <NUM> cannot be restarted, and it is difficult to ensure the negative pressure of the booster. This situation is undesirable especially in the relatively high vehicle speed range in which a relatively large brake force is required before stopping. According to the processing shown in <FIG>, it is possible to reduce the situation where the negative pressure of the booster cannot be ensured in the relatively high vehicle speed range, and to improve safety.

In addition, according to the processing shown in <FIG>, as described above, even in the case where the open circuit fault of the battery <NUM> is detected, the deceleration S&S is permitted in the vehicle speed range at or below the predetermined value V1 (the stop S&S is also permitted). Thus, it is possible to prevent the situation where the deceleration S&S and/or the stop S&S are not performed any longer due to misdetection of the open circuit fault of the battery <NUM>, and to ensure marketability with respect to the misdetection. That is, it is possible to reduce the situation where the opportunity for improving fuel economy is lost due to misdetection of the open circuit fault of the battery <NUM>. In addition, in the case where the open circuit fault of the battery <NUM> is not misdetected, if the deceleration S&S or the stop S&S is initiated, there will be the situation where the engine <NUM> cannot be restarted even if the negative pressure of the booster is insufficient thereafter. This situation is undesirable; however, since it is in a state where the vehicle speed is <NUM> or within a low vehicle speed range at or below the predetermined value V1, the brake force required for achieving stop state or maintaining the stop state is low, and it is possible to ensure the required safety. In addition, in the processing shown in <FIG>, as described above, the method for detecting the open circuit fault of the battery <NUM> (the predetermined range ΔA1 and/or predetermined time ΔT1) tends to give priority to the safety so that misdetection easily occurs, thus it can be contemplated that this situation rarely occurs. Thus, according to the processing shown in <FIG>, it is possible to not only ensure the negative pressure of the booster, but also achieve the improvement of fuel economy.

In addition, according to the processing shown in <FIG>, as described above, the open circuit fault of the battery <NUM> is detected if the state where the current of the battery is within the predetermined range ΔA1 has continued for the predetermined time ΔT1. This method for detecting the open circuit fault of the battery <NUM> is especially suitable for detecting the open circuit fault of the battery <NUM> during travel of the vehicle. In addition, as described above, since it is configured such that the E/G stop vehicle speed Vth as the deceleration S&S initiation condition is reduced from the normal value V0 to the predetermined value V1 in the case where the open circuit fault of the battery <NUM> is detected, it is necessary to reliably detect the open circuit fault of the battery <NUM> during travel of the vehicle. This is because the deceleration S&S is a control initiated in the vehicle travel state.

In addition, according to the processing shown in <FIG>, as described above, even in the case where the E/G stop vehicle speed Vth is reduced from the normal value V0 to the predetermined value V1, when the engine has been restarted (that is, when the engine is successfully restarted), the E/G stop vehicle speed Vth is recovered to the normal value V0. That is, the engine having been restarted means misdetection of the open circuit fault of the battery <NUM>, so the E/G stop vehicle speed Vth is recovered to the normal value V0. Thus, as long as thereafter no open circuit fault of the battery <NUM> is detected again, it becomes a state where the deceleration S&S can be initiated in the vehicle speed range higher than the predetermined value V1. Thus, according to the processing shown in <FIG>, it is possible to prevent the deceleration S&S prohibition state from being continuously maintained in the vehicle speed range higher than the predetermined value V1 due to misdetection of the open circuit fault of the battery <NUM>.

In addition, in the processing shown in <FIG>, as described above, in the case where the engine has been restarted in step <NUM> (that is, in the case where the engine is successfully restarted), the E/G stop vehicle speed Vth is recovered to the normal value V0. However, it may also be configured such that after the engine <NUM> has been stopped by the deceleration S&S or the stop S&S, in the case where a battery current at or higher than a predetermined value (e.g., significantly larger than the battery current within the predetermined range ΔA1 used in the above step <NUM>) is detected based on the detected signal of the current sensor <NUM> and/or in the case where a predetermined vehicle load <NUM> is normally operated, etc., the E/G stop vehicle speed Vth is recovered to the normal value V0.

<FIG> is a diagram explaining an example of the method for setting the predetermined value V1. In <FIG>, the horizontal axis represents the vehicle speed, and the vertical axis represents the E/G restart failure probability [ppm]. In addition, ppm represents parts per million. The so-called E/G restart failure probability means the probability to become the situation where the engine <NUM> cannot be restarted after the engine has been stopped by the deceleration S&S or the stop S&S. In <FIG>, of the regions divided by the curve C1, the upper region "NG" is a region in which the situation where the engine <NUM> cannot be restarted is not allowable, and the lower region "OK" is a region in which the situation where the engine <NUM> cannot be restarted is allowable. The curve C1 is set based on the design principle, and typically, it may represent the relation that the lower the vehicle speed is, the higher the allowable E/G restart failure probability is.

In <FIG>, the E/G restart failure probability P1 corresponds to the E/G restart failure probability in the case of using the method for detecting the open circuit fault of the battery <NUM> in step <NUM> of <FIG>. In other words, the E/G restart failure probability P1 corresponds to the precision (reliability) for detecting the open circuit fault of the battery <NUM> in step <NUM> of <FIG>. At this time, if the E/G stop vehicle speed Vth is the normal value V0, as shown in <FIG>, the E/G restart failure probability P1 falls within the region "NG". Therefore, as shown in <FIG>, the predetermined value V1 is set so that the E/G restart failure probability P1 falls within the region "OK".

<FIG> is a flowchart showing another example of processing performed by the abnormality detection part <NUM> and the control suppression part <NUM>. The processing routine shown in <FIG> is initiated, for example, upon turning-on of the ignition switch of the vehicle, and then is repeatedly performed at a predetermined processing cycle time, until the ignition switch is turned off. However, the processing in step <NUM>, step <NUM> and step <NUM> is only performed during travel of the vehicle.

The processing shown in <FIG> differs from that shown in <FIG> mainly in the addition of step <NUM>. The processing in step <NUM>, step <NUM>, step <NUM> and step <NUM> shown in <FIG> may be the same as the processing in step <NUM>, step <NUM>, step <NUM> and step <NUM> shown in <FIG>. Hereinafter, the processing unique to <FIG> will be described.

As with the processing shown in <FIG>, in the processing shown in <FIG>, as a premise, it is configured such that the deceleration S&S is performed in a deceleration state with a speed at or below the E/G stop vehicle speed Vth. In other words, the deceleration S&S initiation conditions include the deceleration state with a speed at or below the E/G stop vehicle speed Vth. In addition, in the example shown in <FIG>, since the deceleration S&S prohibition flag is not used, the deceleration S&S prohibition flag may be omitted. Therefore, the processing shown in <FIG> is suitable for the situation where the S&S control part <NUM> performs the processing shown in <FIG>.

In step <NUM>, the abnormality detection part <NUM> determines again whether or not an open circuit fault occurs in the battery <NUM> in the same manner as that in step <NUM> shown in <FIG>. In step <NUM>, if it is determined that the state where the current of the battery is within the predetermined range ΔA2 has continued for the predetermined time ΔT2, the processing proceeds to step <NUM>, otherwise proceeds to step <NUM>. Therefore, in the processing shown in <FIG>, even if it is not determined to be YES in step <NUM>, when it is determined that the state where the current of the battery is within the predetermined range ΔA2 has continued for the predetermined time ΔT2, the E/G stop vehicle speed Vth is recovered to the normal value V0.

In step <NUM>, the control suppression part <NUM> determines whether or not the engine <NUM> has been stopped by the deceleration S&S or the stop S&S. Whether or not the engine <NUM> has been stopped by the deceleration S&S or the stop S&S can be determined based on the information obtained from the S&S control part <NUM>. If it is determined that the engine <NUM> has been stopped by the deceleration S&S or the stop S&S, the processing proceeds to step <NUM>, otherwise returns to step <NUM>.

According to the processing shown in <FIG>, the same effects can be achieved as the processing shown in <FIG>. In addition, according to the processing shown in <FIG>, even if there is temporarily a positive determination in step <NUM> such that the E/G stop vehicle speed Vth is set to the predetermined value V1, before the deceleration S&S or the stop S&S is initiated thereafter, it is possible to recover the E/G stop vehicle speed Vth to the normal value V0 according to the determination result in step <NUM>. That is, even in the case where the open circuit fault of the battery <NUM> is temporarily detected in step <NUM> such that the E/G stop vehicle speed Vth is set to the predetermined value V1, thereafter whether or not the open circuit fault occurs in the battery <NUM> will be confirmed again. Thus, even in the case where the open circuit fault of the battery <NUM> is misdetected in step <NUM>, it is possible to recover the E/G stop vehicle speed Vth to the normal value V0 by the redetermination thereafter. As a result, it is possible to reduce the situation where the opportunity for improving fuel economy is lost due to misdetection of the open circuit fault of the battery <NUM>.

In addition, in the processing shown in <FIG>, in the case where the open circuit fault of the battery <NUM> is temporarily detected in step <NUM> such that the E/G stop vehicle speed Vth is set to the predetermined value V1, the determination in step <NUM> is repeatedly performed at a predetermined processing cycle time, until the engine <NUM> is stopped by the deceleration S&S or the stop S&S. However, the determination in step <NUM> may be performed, before the engine <NUM> is stopped by the deceleration S&S or the stop S&S, only once, or may be performed predetermined times no less than twice. In addition, the determination in step <NUM> may be performed, before the engine <NUM> is stopped by the deceleration S&S or the stop S&S, every predetermined period of time (>> the predetermined processing cycle time) has elapsed, and may also be performed upon every predetermined travel distance.

<FIG> is a flowchart showing another example of processing performed by the abnormality detection part <NUM> and the control suppression part <NUM>. The processing routine shown in <FIG> is initiated, for example, upon turning-on of the ignition switch of the vehicle, and then is repeatedly performed at a predetermined processing cycle time, until the ignition switch is turned off. However, the processing in step <NUM> and step <NUM> is only performed during travel of the vehicle.

In step <NUM>, the abnormality detection part <NUM> calculates the time duration ΔTN during which the current of the battery continues to be within the predetermined range ΔA1 based on the detected value of the current sensor <NUM>. The initial value of the time duration ΔTN is <NUM>. The time duration ΔTN may be calculated by a counter. For example, it may be configured such that within a certain processing cycle time, in the case where the current of the battery is within the predetermined range ΔA1, a count value is incremented by <NUM>, and in the case where the current of the battery is not within the predetermined range ΔA1, the count value is decremented by <NUM>. In this case, the count value × the processing cycle time corresponds to the time duration ΔTN. The time duration ΔTN is an index representative of the possibility of open circuit fault of the battery <NUM>, and the longer the time duration ΔTN is, the higher the possibility that an open circuit fault occurs in the battery <NUM> is.

In step <NUM>, the control suppression part <NUM> sets the E/G stop vehicle speed Vth to a value V(ΔTN) corresponding to the time duration ΔTN calculated in the above step <NUM>. The value V(ΔTN) is set in such a manner that the longer the time duration ΔTN is, the smaller the value V(ΔTN) is. For example, the value V(ΔTN) can be set to be variable based on the concept shown in <FIG>. Specifically, the E/G restart failure probability P1 is converted according to the time duration ΔTN (e.g. the E/G restart failure probability P1 is in proportion with the time duration ΔTN) and derived, and the value V(ΔTN) is set corresponding to the time duration ΔTN so that the E/G restart failure probability P1 falls within the region "OK".

Alternatively, simply, the value V(ΔTN) when the time duration ΔTN is <NUM> may be the normal value V0 (refer to <FIG>). In addition, the value V(ΔTN) when the time duration ΔTN becomes the predetermined time ΔT1 may be the predetermined value V1. In this case, the value V(ΔTN) may be decreased linearly or non-linearly from the normal value V0 to the predetermined value V1 with the increase of the time duration ΔTN. At this time, in the case where the time duration ΔTN exceeds the predetermined time ΔT1, the value V(ΔTN) may either be maintained at the predetermined value V1, or decreased towards <NUM> with the increase of the time duration ΔTN.

In step <NUM>, the control suppression part <NUM> determines whether or not the engine <NUM> has been stopped by the deceleration S&S or the stop S&S. Whether or not the engine <NUM> has been stopped by the deceleration S&S or the stop S&S can be determined on the basis of the information obtained from the S&S control part <NUM>. In the case where it is determined that the engine <NUM> has been stopped by the deceleration S&S or the stop S&S, the processing proceeds to step <NUM>, otherwise returns to step <NUM>.

In step <NUM>, the abnormality detection part <NUM> resets the time duration ΔTN to the initial value <NUM>.

According to the processing shown in <FIG>, the E/G stop vehicle speed Vth as the deceleration S&S initiation condition is set to a value V(ΔTN) corresponding to the time duration ΔTN. As described above, the time duration ΔTN is the duration during which the current of the battery continues to be within the predetermined range ΔA1, and is an index representative of the possibility of open circuit fault of the battery <NUM>. In addition, as described above, the value V(ΔTN) is set in such a manner that the longer the time duration ΔTN is, the smaller it is. Therefore, the value V(ΔTN) is set in such a manner that the higher the possibility of open circuit fault of the battery <NUM> is, the smaller it is. Thus, with the possibility of open circuit fault of the battery <NUM> being higher, it is possible to decrease the E/G stop vehicle speed Vth as the deceleration S&S initiation condition to a greater extent.

In addition, in the processing shown in <FIG>, the time duration ΔTN may also be reset in the case where a predetermined condition other than restart of the engine <NUM> is satisfied. For example, based on the concept shown in <FIG>, the time duration ΔTN may be reset if the state where the current of the battery is within the predetermined range ΔA2 has continued for the predetermined time ΔT2.

While various embodiments have been described in detail, the present invention is not limited to the specific embodiments, and various variations and modifications can be made within the scope as defined in the following claims.

Claim 1:
A vehicle control apparatus, comprising:
a current sensor (<NUM>) configured to detect a current value of a battery (<NUM>);
a voltage sensor (<NUM>) configured to detect a voltage value of the battery (<NUM>); and
a processing device (<NUM>) configured to
detect an open circuit fault of the battery (<NUM>) in a vehicle stop state with a vehicle speed at <NUM> based on the voltage value of the voltage sensor (<NUM>) detected in the vehicle stop state;
detect the open circuit fault of the battery (<NUM>) in a vehicle non-stop state with a vehicle speed higher than <NUM> based on the current value of the current sensor (<NUM>) detected in the vehicle non-stop state;
initiate the idling stop control in the vehicle stop state under initiation conditions that the open circuit fault is not detected based on the voltage value; and
suppress to initiate the idling stop control in the vehicle non-stop state, in response to detecting the open circuit fault based on the current value;
the vehicle control apparatus being characterized in that the processing device (<NUM>) is further configured to
permit to initiate the idling stop control in the vehicle stop state under the initiation conditions, even in the case where the open circuit fault has been detected based on the current value in the vehicle non-stop state.