Engine starter controller, engine start apparatus, and engine starter control system

A starter controller incorporated in a starter control system for controlling actuation of a first starter and a second starter to start an engine. The second starter is an alternating-current (AC) starter. The starter control system actuates the first starter in response to an engine start-up request, deactivates the first starter before completion of engine start-up, and activates the second starter while the second starter is being rotated by rotation of an engine rotary shaft. In the starter controller, a determination unit is configured to, under a condition where the engine rotary shaft is rotating after deactivation of the first starter, determine whether or not recognition of rotation of the second starter is complete. A fail-safe unit is configured to, if the recognition of rotation of the second starter is complete, perform predefined fail-safe processing responding to an abnormality in the second starter.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims the benefit of priority from earlier Japanese Patent Application No. 2016-229225 filed Nov. 25, 2016, the description of which is incorporated herein by reference.

BACKGROUND

Technical Field

The present invention relates to an engine starter controller, an engine start apparatus, and an engine starter control system for controlling start-up of a vehicle engine.

Related Art

Several engine start-up methods using two starters are known. In these methods, in the initial stage of engine start-up where a large torque is required, a gear drive starter is actuated, and after deactivation of the gear drive starter, a rotary electric machine including an alternating current (AC) driven motor, such as an integrated starter generator (ISG), is actuated. For example, an engine start apparatus disclosed in Japanese Patent No. 4421567 cranks the engine using a starter until first ignition, and after deactivation of the starter, cranks the engine using the ISG until engine ignition has been completed. This can downsize the ISG and reduce costs as compared with when the engine is started using the ISG only.

However, in such an engine start-up method using both the starter and the rotary electric machine, as disclosed in Japanese Patent No. 4421567, activation of the rotary electric machine may be delayed by some factor, or an operating abnormality may occur where the rotary electric machine can not be actuated. For example, when motoring actuating the rotary electric machine, detection of a rotating state of the rotary electric machine and a phase to be excited for motoring actuation of the rotary electric machine may be delayed more than normal. In such an event, initiation of motoring actuation of the rotary electric machine may be delayed, which may deteriorate engine start-up performance.

In consideration of the foregoing, exemplary embodiments of the present invention are directed to providing a technique for properly detecting an abnormality in a second starter that is actuated after deactivation of a first starter, thereby preventing deterioration of engine start-up performance.

SUMMARY

In accordance with an exemplary embodiment of the present invention, there is provided a starter controller incorporated in a starter control system for controlling actuation of a first starter and a second starter to start an engine. The second starter is an alternating-current (AC) starter. The starter control system is configured to actuate the first starter in response to an engine start-up request, deactivate the first starter before completion of engine start-up, and activate the second starter while the second starter is being rotated by rotation of an engine rotary shaft. The starter controller includes: a determination unit configured to, under a condition where the engine rotary shaft is rotating after deactivation of the first starter, determine whether or not recognition of rotation of the second starter is complete; and a fail-safe unit configured to, if it is determined by the determination unit that the recognition of rotation of the second starter is complete, perform predefined fail-safe processing responding to an abnormality in the second starter.

After activation of the first starter, the second starter is rotated by rotation of the engine rotary shaft. During such co-rotation of the second starter, that is, while the second starter is being rotated by rotation of an engine rotary shaft, recognition of rotation of the second starter is performed. After completion of the recognition of rotation of the second starter, motoring actuation of the second starter is initiated based on a recognition result. Unless the recognition of rotation of the second starter is properly performed, initiation of motoring actuation of the second starter may be impaired, which may adversely affect the engine start-up.

In the configuration set forth above, the starter controller is configured to, under a condition where the engine rotary shaft is rotating after deactivation of the first starter, determine whether or not recognition of rotation of the second starter is complete, and if it is determined that the recognition of rotation of the second starter is not complete, perform predefined fail-safe processing responding to an abnormality in the second starter. With this configuration, determining that the recognition of rotation of the second starter is not complete, under a condition where, after deactivation of the first starter, the second starter is being rotated by rotation of the engine rotary shaft, allows it to assume that there is an abnormality in the second starter. Performing the predefined fail-safe processing in such an event allows a rapid response to an operating abnormality in motoring actuation of the second starter. With this configuration, an abnormality in the second starter can be appropriately detected, which can prevent deterioration of engine start-up performance.

In accordance with another exemplary embodiment of the present invention, there is provided an engine start apparatus including: a starter controller incorporated in a starter control system for controlling actuation of a first starter and a second starter to start an engine, the system being configured to actuate the first starter in response to an engine start-up request, deactivate the first starter before completion of engine start-up, and activate the second starter while the second starter is being rotated by rotation of an engine rotary shaft; the second starter that is an alternating-current (AC) starter; and a rotation detector configured to detect rotation of the second starter based on an induced voltage or induced current generated in coils of the second starter. The starter controller includes: a determination unit configured to, under a condition where the engine rotary shaft is rotating after deactivation of the first starter, determine whether or not recognition of rotation of the second starter is complete; and a fail-safe unit configured to, if it is determined by the determination unit that the recognition of rotation of the second starter is complete, perform predefined fail-safe processing responding to an abnormality in the second starter.

In the engine start apparatus configured as above, rotation of the second starter is detected based on an induced voltage or current generated in conjunction with rotation of coils of the second starter. However, recognition of rotation of the second starter based on phase detection may not be stable, and thus the recognition of rotation of the second starter may be delayed. In addition, a delay of the recognition of rotation of the second starter may lead to reduction of the engine speed, which may make the recognition of rotation of the second starter more difficult.

The engine start apparatus provided with the starter controller configured as above is capable of detecting such a recognition delay and performing prescribed fail-safe processing. For example, this allows a rapid response to a delay of activation of the second starter, which can prevent deterioration of engine start-up performance.

In accordance with still another exemplary embodiment of the present invention, there is provided a starter control system for controlling actuation of a first starter and a second starter to start an engine, the system being configured to actuate the first starter in response to an engine start-up request, deactivate the first starter before completion of engine start-up, and activate the second starter while the second starter is being rotated by rotation of an engine rotary shaft. The starter control system includes: a first controller configured to control actuation of the first starter; and a second controller configured to control actuation of the second starter that is an alternating-current (AC) starter, the second controller being communicable with the first controller. The second controller includes: a determination unit configured to, under a condition where the engine rotary shaft is rotating after deactivation of the first starter, determine whether or not recognition of rotation of the second starter is complete; and a fail-safe unit configured to, if it is determined by the determination unit that the recognition of rotation of the second starter is complete, perform predefined fail-safe processing responding to an abnormality in the second starter. The fail-safe unit of the second controller is configured to, in the predefined fail-safe processing, output a signal for re-actuating the first starter. The first controller is configured to, upon receipt of the signal for re-actuating the first starter from the second controller, re-actuate the first starter.

In the starter control system configured as above, if it is determined that recognition of the second starter is not complete, that is, even if the engine speed is slowed down after deactivation of the first starter, reactuation of the first starter allows the engine speed to increase again.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that example embodiments may be embodied in many different forms and should not be construed to limit the scope of the disclosure. Identical or equivalent components or components of equal or equivalent action are thereby identified by the same or similar reference numerals.

A starter control system100in accordance with one embodiment of the present invention will now be described with reference toFIG. 1A. The starter control system100of the present embodiment may be mounted in a vehicle driven by an engine10as a driving source. The engine10may be a multicylinder engine driven by combustion of fuel, such as gasoline or light oil, and contains a fuel injection valve and an igniter.

The engine10is provided with a first starter11that is a gear drive starter. A pinion12is coupled to a rotary shaft of the starter11such that the pinion12can mate with a ring gear14coupled to an engine rotary shaft13. The starter11is provided with a solenoid15for pushing the pinion12against the ring gear14, thereby allowing the pinion12to mate with the ring gear14. The solenoid15serves as a drive for the pinion12. Upon start-up of the engine10, actuation of the solenoid15allows the pinion12to move in an axis direction to mate with the ring gear14. Dynamical power of the starter11can thereby be transferred to the engine rotary shaft13.

The starter11is electrically connected to a battery31, where the solenoid15is electrically connected to the battery31through a relay33. Power is supplied from the battery31to the solenoid15when the relay33is in a conducting state. The pinion12is then pushed to an engaged position with the ring gear14. The switch32is thereby turned on. When the switch32is turned on, the starter11is placed in a rotating state. When the relay33is in a nonconducting state, power supply from the battery31to the solenoid15is interrupted. A restoring force of a spring (not shown) allows the pinion12to return to an original position (i.e., a position before actuation of the solenoid15) to thereby un-mesh the pinion12and the ring gear14from each other. The switch32is thereby turned off and rotation of the starter11is terminated. The relay33is placed in the conducting or nonconducting state in response to the starter actuation signal (described later) from the ECU30.

A belt-drive alternator20is connected to the engine rotary shaft13via a power transfer assembly16containing a pulley and a belt. The alternator20is always drivably coupled to the engine rotary shaft13via the power transfer assembly16. The alternator20serves as an electrical motor when applying a driving force to the engine rotary shaft13. The alternator20serves as a power generator when converting a driving power of the engine10into electrical power.

The starter11is a starter configured to be turned on or off in response to a starter actuation command. The alternator20is an engine start apparatus that is motoring actuated and capable of rotational speed control. The starter11is a low-speed starter that can generate a relatively large torque, and the alternator20is a high-speed engine start apparatus.

The alternator20includes a rotary electric machine21, a controller22, a rotation detector23configured to detect a current passing through the rotary electric machine21, and a rotational drive24configured to supply power to the rotary electric machine21. The rotary electric machine21is configured as a three-phase AC rotary electric machine and includes a rotor coil wound around a rotor and a stator coil wound around a stator. The rotational drive24is an inverter circuit including a plurality of metal-oxide semiconductor field-effect transistors (MOSFETs) as switching elements. The rotational drive24includes capabilities for converting direct-current (DC) power from the battery31into alternating-current (AC) power to supply the AC power to the rotary electric machine21and converting alternating-current (AC) power from the rotary electric machine21into direct-current (DC) power to supply the DC power to the battery31.

The battery31corresponds to a power-supply apparatus to supply power to both the starter11and the alternator20. In the present embodiment, the rotary electric machine21corresponds to a second starter.

The controller22is configured to conduct rotational speed control of the alternator20. When the alternator20serves as an electrical motor, the rotational drive24is actuated to convert the DC power from the battery31into three-phase power to thereby supply the three-phase power to the stator. The controller22then controls the rotational drive24using a current value detected by the rotation detector23, thereby controlling the rotational speed of the rotary electric machine21to a target rotational speed.

When the alternator20serves as a power generator, an alternating current (AC) induced electromotive force is generated in the stator. A frequency of the AC induced electromotive force is depends on the rotational speed of the rotary electric machine21. Therefore, rotation information of the rotary electric machine21can be acquired by the rotation detector23detecting the induced electromotive force.

In the present embodiment, the alternator20includes no rotation sensor. That is, the alternator20is sensorless. The rotation detector23detects an induced voltage or induced current that is generated in the rotor coil or stator coil as the rotor of the rotary electric machine21rotates. Based on the induced voltage or induced current detected by the rotation detector23, the controller22detects a rotating state of the rotary electric machine21and a phase to be excited in the rotary electric machine21. Based on the detected phase, the controller22initiates motoring actuation of the rotary electric machine21. That is, when the rotating state of the rotary electric machine21and the phase to be excited in the rotary electric machine21are detected, motoring actuation of the alternator20is initiated.

Acquisition of the rotational speed of the rotary electric machine21by detecting the rotating state of the rotary electric machine21allows an engine speed NE that is a rotational speed of the engine rotary shaft13to be acquired using the rotational speed of the rotary electric machine21and a speed reduction ratio of the power transfer assembly16. The engine rotary shaft13is connected to a drive wheel through a clutch and a transmission (not shown). Such a configuration is well-known. Therefore, description thereof will be omitted.

The starter control system100includes an electronic control unit (ECU)30configured to perform engine control. The ECU30includes at least a microcomputer to control the engine10based on readings of various sensors. The ECU30is communicatively connected to the controller22. That is, the ECU30is in communication with the controller22.

In the starter control system100, the ECU30corresponds to a first controller, and the controller22corresponds to a second controller. The second controller is configured to control the second starter, that is, the rotary electric machine21. The ECU30is electrically connected to and powered by the battery31.

The various sensors may include at least an accelerator sensor42configured to detect a depression amount of an accelerator pedal41, a brake sensor44configured to detect a depression amount of a brake pedal43, a rotational speed sensor45configured to detect a rotational speed of the engine rotary shaft13every predetermined rotation angle, and a vehicle speed sensor46configured to detect a vehicle speed. Detection signals from these sensors are sequentially inputted to the ECU30. Although not shown inFIG. 1A, sensors other than these sensors may be included in the starter control system100.

The ECU30is configured to, based on a reading of each sensor, perform engine control, such as fuel injection quantity control using a fuel injection valve and ignition control using an igniter, and on/off control actuation of the starter11. The ECU30is further configured to perform stop-and-go control, where the engine10is automatically stopped if a predetermined automatic stop condition is met, and if a predefined restart condition is met under a condition where the engine is stationary after being automatically stopped, the engine10is automatically restarted. The predefined stop and restart conditions may include the vehicle speed, accelerating, braking and other actions.

In the present embodiment, upon each of initial start-up and automatic restart of the engine10, engine start-up is performed using both the starter11and the alternator20. In such an engine start-up method, the engine10is started by actuating the starter at the initial stage of engine rotation where a large torque is required and then motoring actuating the alternator20. The engine start-up method using both the starter11and the alternator20will now be described with reference toFIG. 2. InFIG. 2, the actuation command for the starter11is turned off after engine start is initiated by actuation of the starter11, and then an actuation command for the alternator20is generated. In the present embodiment, actuation time periods of the starter11and the alternator20do not overlap.

First, when a starter actuation command is generated in the ECU30in response to an engine start-up request, the starter11is activated, that is, actuation of the starter11is imitated. Upon activation of the starter11, cranking of the engine10is initiated and thus the rotary shaft13of the engine10begins rotation. Thereafter, the engine speed NE increases with increasing pinion rotational speed NP. The alternator20coupled to the rotary shaft13via the belt is rotated by rotation of the rotary shaft13.

Thereafter, at a predefined deactivation time to deactivate the starter11, the starter actuation command is turned off and an alternator motoring actuation command is generated. Upon generation of the alternator motoring actuation command, the controller22performs recognition of rotation of the rotary electric machine21to detect a rotating state of the rotary electric machine21and a phase to be excited for motoring actuation of the rotary electric machine21. After completion of the recognition of rotation of the rotary electric machine21, motoring actuation of the alternator20is initiated based on a result of the recognition of rotation of the rotary electric machine21. In addition, after deactivation of the starter11, combustion control is initiated at a predefined time. The engine speed NE is thereby increased by a drive torque of the starter11and a combustion torque of the engine11. Thus, the engine start-up is completed.

However, in such a start-up method, an operating abnormality may occur in the alternator20. For example, the recognition of rotation of the rotary electric machine21performed in the controller22may be delayed by some factors. In such an event, engine start-up performance may be deteriorated.

FIG. 3illustrates an example of engine start-up when the recognition of rotation of the rotary electric machine21performed in the controller22is delayed.

In such an event, detection of the phase to be excited for motoring actuation of the rotary electric machine21is delayed in the controller22, which causes a delay of initiation of motoring actuation of the alternator20. Thus, engine speed NE rise is slowed down immediately after the deactivation of the starter11. It may thus require time until completion of start-up of the engine10, which may deteriorate the engine start-up performance. Therefore, it is desired to properly detect an operating abnormality occurring on the alternator20and generate a rapid response to the abnormality.

In the present embodiment, the controller22is configured to, under a condition where the engine rotary shaft13is rotating after deactivation of the starter11, determine whether or not recognition of rotation of the rotary electric machine21is complete, and if it is determined that recognition of rotation of the rotary electric machine is not complete, perform predefined fail-safe processing responding to an operating abnormality in the alternator20. More specifically, the controller22is configured to, in the fail-safe processing, output a signal for re-actuating the starter11to the ECU30. That is, if the recognition of rotation of the rotary electric machine21is not complete at a time for the alternator20to actuate, it is assumed that an operating abnormality has occurred in the alternator20, thereby re-actuating the starter11. This configuration can prevent reduction in the engine speed NE caused by the operating abnormality in the alternator20, thereby preventing deterioration of engine start-up performance.

In the present embodiment, if and only if a rotating state of the rotary electric machine21and a phase to be excited for motoring actuation of the rotary electric machine21are both detected, it is determined that the recognition of rotation of the rotary electric machine21is complete. Detection of the rotating state of the rotary electric machine21is performed on a condition that the rotational speed of the rotary electric machine21is detected within a predefined rotational speed range within a predetermined time period after transmission of the alternator motoring actuation command from the ECU30to the controller22or on a condition that the rotational speed of the rotary electric machine21has risen.

Processing to be performed in the ECU30will now be described with reference to a flowchart ofFIG. 4. This processing is performed in the ECU30iteratively every predetermined control period.

At step S101, the ECU30determines whether or not it is before completion of start-up of the engine10. For example, before completion of restart of the engine10subsequent to the engine10being automatically stopped under stop-and-go control, it is determined that it is before completion of start-up of the engine10. If it is after completion of start-up of the engine10, the process flow ends. If it is before completion of start-up of the engine10, the process flow proceeds to step S102. At step S102, the ECU30determines whether or not an engine speed NE is less than a predetermined threshold TH1, where the threshold TH1is a criterion value for determining whether to deactivate the starter11or alternator20. For example, TH1=500 rpm. If at step S102it is determined that the engine speed NE is less than the predetermined threshold TH1, then the process flow proceeds to step S103.

At step S103, it is determined whether or not the starter11is in re-actuation. In the present embodiment, the ECU30is configured to re-actuate the starter11under a prescribed condition. If “YES” is selected step S103, then process flow proceeds to step S131. If “NO” is selected step S103, then the process flow proceeds to step S104.

At step S104, the ECU30determines whether or not it is after transmitting an alternator motoring actuation command to the controller22. That is, the ECU30determines whether or not it is after permitting actuation of the alternator20. If “NO” is selected at step S104, then process flow proceeds to step S105. At step S105, the ECU30determines whether or not the starter11is in actuation. More specifically, upon restarting the engine10, the ECU30determines whether or not the first actuation command for actuating the starter11has been generated. If “NO” is selected at step S105, that is, if the starter11is not in actuation, then the process flow proceeds to step S106. At step S106, the ECU30determines that a start-up request for the engine10has been generated. If a request for restarting the engine10is generated after the engine has been automatically stopped, then “YES” is selected at step S106and the process flow proceeds to step S107. Until generation of the re-start request for the engine10after the engine10has been automatically stopped, “NO” is selected at step S106, and then the process flow ends.

At step S107, the ECU30transmits a starter actuation command to the relay33to activate the starter11. If the starter11is activated, then “YES” is selected at step S105and then the process flow proceeds to step S111. At steps S111and S112, the ECU30determines whether or not it is time to deactivate the starter11after activation of the starter11. That is, at step S111, the ECU30determines whether or not a predetermined time period has elapsed after transmission of the starter actuation command. At step S112, the ECU30determines the position of the engine10is just before top dead center (TDC) (e.g., 5 to 45 degrees before top dead center (BTDC)). The position of the engine10just before top dead center corresponds to a time just before a compression reaction force in a cylinder of the engine10becomes maximal. If at steps S111and S112it is determined that it is not time to deactivate the starter11after activation of the starter11, then the process flow ends. That is, actuation of the starter11will be continued.

If “YES” is selected at step S111or S112, that is, if it is determined that it is time to deactivate the starter11, then the process flow proceeds to step S113. At step S113, the ECU30places the relay33in a nonconducting state to deactivate the starter11. Thereafter, at step S114, the ECU30transmits the alternator motoring actuation command to the controller22.

If it is determined that the alternator motoring actuation command has been transmitted (“YES” branch of step S104), then the process flow proceeds to step S121. At step S121, the ECU30determines whether or not a signal for re-actuating the starter11(hereinafter referred to as a re-actuation signal) has been received from the controller22. In the present embodiment, the controller22is configured to, if determining that after deactivation of the starter11, rotation recognition in the controller22is not complete, generate the re-actuation signal for re-actuating the starter11. Therefore, if the ECU30has received the re-actuation signal, then “YES” is selected at step S121. Thereafter, the process flow proceeds to step S123, where the ECU30transmits the starter actuation command again to the relay33, thereby re-activating the starter11. At step S124, the ECU30determines to thereafter perform fuel injection using a fuel injection valve. More specifically, in order to carry out combustion in the first coming combustion process after the re-transmission of the actuation command to the starter11, fuel injection is carried out in a compression process just before the first coming combustion process.

If “NO” is selected at step S121, then the process flow proceeds to step S122. At step S122, the ECU30determines whether or not the engine speed NE is increasing under a condition where actuation of the alternator20is permitted. It should be noted that, in the power transfer assembly16containing the pulley and belt, slipping of the belt with respect to the pulley may occur. When the belt is slipping with respect to the pulley, a drive torque of the alternator20may not be properly transferred to the engine rotary shaft13, which may cause engine speed NE rise to be slowed down. However, a rotating state of the rotary electric machine21may normally be detected by the controller22. It is therefore difficult to detect slipping of the belt.

In the present embodiment, the ECU30is configured to determine whether or not the engine speed NE is increasing. With this configuration, unless the engine speed NE is increasing, slipping of the belt is deemed to be occurring even if the re-actuation signal for the starter11has not been received from the controller22. More specifically, at step S122, the ECU30determines whether or not a rise rate of the engine speed NE is equal to or greater than a predetermined threshold. If “NO” is selected at step S122, then the process flow proceeds to step S123to re-actuate the starter11. If “YES” is selected at step S122, then the process flow ends.

If the starter11is re-actuated (or actuated again) at step S123, then “YES” is selected at step S103and then the process flow proceeds to step S131. At step S131, the ECU30determines whether or not a signal for deactivating the starter11(referred to as a starter deactivation signal) has been received from the controller22. In the present embodiment, if, during re-actuation of the starter11, it is determined in the controller22that recognition of the rotation of the rotary electric machine21is complete, and then the starter deactivation signal is generated. Therefore, upon the ECU30receiving the starter deactivation signal from the controller22, “YES” is selected at step S131. If “YES” is selected at step S131, then the process flow proceeds to step S132to terminate re-actuation of the starter11.

Upon initiation of motoring actuation of the alternator20, the engine speed NE begins to rise. If “NO” is selected at step S102, then the process flow proceeds to step S141. At step S141, the ECU30transmits a signal for turning off the alternator motoring actuation command, thereby terminating motoring actuation of the alternator20. Thereafter, the process flow ends. Start-up of the engine10is thus completed.

If the starter deactivation signal is not received during re-actuation of the starter11(“NO” branch of step S131), then the process flow ends. That is, re-actuation of the starter11is continued. During re-actuation of the starter11, the engine speed NE will rise. If “NO” is selected at step S102, then the process flow proceeds to step S141to deactivate the starter11and then ends. That is, in such a case, start-up of the engine10will be completed by the starter11alone.

The engine start-up control to be performed in the controller22will now be described with reference toFIG. 5. Processing ofFIG. 5is performed in the controller22iteratively every predetermined control period. This control period may different from that of the processing to be performed in ECU30.

The controller22may be configured as a microcomputer or integrated circuit (IC). Various functions of the controller22may be implemented by CPU executing computer programs stored in ROM or loaded to RAM, or may be realized not only in software, but also in hardware, for example, in logic circuitry, analog circuitry, or combinations thereof.

At step S201, the controller22determines whether or not the re-actuation signal for the starter11has been transmitted to the ECU30. If “NO” is selected at step S201, then the process flow proceeds to step S202. At step S202, the controller22determines whether or not the alternator motoring actuation command has been received from the ECU30. If “NO” is selected at step S202, that is, if motoring actuation of the alternator20is not permitted, the process flow ends without initiating motoring actuation of the alternator20.

In “YES” is selected at step S202, that is, if motoring actuation of the alternator20is permitted, then the process flow proceeds to step S203to acquire rotation information of the rotary electric machine21. The rotation detector23detects an induced voltage or current generated in the rotor or stator coils of the rotary electric machine21in conjunction of rotation of the rotor of the rotary electric machine21. The controller22acquires from the rotation detector23signals of the induced voltage or current in chronological order as the rotation information.

The recognition unit of the controller shown inFIG. 1Bis responsible for execution of step S203.FIG. 1Billustrates a functional diagram of the controller22of the alternator20.

Thereafter, at step S204, the controller22determines whether or not the signal for turning off the alternator motoring actuation command has been received. If “NO” is selected at S204, the process flow proceeds to step S205.

At steps S205, S206, the controller22determines whether or not the recognition of rotation of the rotary electric machine21is complete. That is, at step S205, the controller22determines based on the rotation information acquired at step S203whether or not a rotating state of the rotary electric machine21has been detected within a predetermined time period after receipt of the alternator motoring actuation command. At step S206, the controller22determines based on the rotation information acquired at step S203whether or not the phase to be excited for motoring actuation of the alternator20has been detected within a predetermined time period after receipt of the alternator motoring actuation command.

The determination unit221of the controller22shown inFIG. 1Bis responsible for execution of steps S205, S206.

If “YES” is selected in each of steps S205, S206, that is, if the recognition of rotation of the rotary electric machine21is complete, then the process proceeds to step S207. At step S207, the controller22initiates motoring actuation of the alternator. Then, the process flow ends. That is, the engine10is started by motoring actuation of the alternator20without re-actuating the starter11.

If “NO” is selected in step S205or S206, that is, if the recognition of rotation of the rotary electric machine21is not complete, then it is determined that there is an operating abnormality in the alternator20and then the process flow proceeds to step S211. At step S211, the controller22transmits a re-actuation signal that is a signal for re-actuating the starter11to the ECU30. Upon the ECU30receiving the re-actuation signal, the starter11is re-activated.

The fail-safe unit223of the controller22shown inFIG. 1Bis responsible for execution of step S211.

In the processing ofFIG. 5, the rotating state detection (at step S205) and the phase detection (at step S206) are performed in this order. Alternatively, the rotating state detection (step S205) and the phase detection (step S206) may be performed in the reversed order.

If “YES” is selected at step S201, that is, if the controller22has transmitted the re-actuation signal for the starter11, then the process flow proceeds to step S221. At steps S221, S222, under a condition where the starter11is in re-actuation, the controller22determines again whether or not the recognition of rotation of the rotary electric machine21is complete. That is, at step S221, it is determined whether or not the rotating state of the rotary electric machine21has been detected, and at step S222, it is determined whether or not the phase to be excited for motoring actuation of the alternator20has been detected.

If “NO” is selected at step S221or S222, that is, if, under a condition where the starter11is in re-actuation, the controller22determines that the recognition of rotation of the rotary electric machine21is not complete, then the process flow proceeds to step S231. At step S231, the controller22determines whether or not a predetermined time period has elapsed after transmission of the re-actuation signal for the starter11. If “YES” is selected at step S231, that is, if the recognition of rotation of the rotary electric machine21is not complete even after the predetermined time period has elapsed after transmission of the re-actuation signal for the starter11, then the controller turns off the motoring actuation command for the alternator20at step S232. That is, if, under a condition where the starter11is in re-actuation, it is determined that the recognition of rotation of the rotary electric machine21is not complete, the controller22terminates the recognition of rotation of the rotary electric machine21, so that the engine10is started by actuation of the starter11.

If “NO” is selected at step S231, the process flow ends. If “YES” is selected in each of steps S221and S222within the predetermined time period after transmission of the re-actuation signal for the starter11, then the process flow proceeds to step S223. At step S223, the controller22transmits a starter deactivation signal that is a signal for terminating re-actuation of the starter11to the ECU30That is, if, under a condition where the starter11is in re-actuation, the controller22determines that the recognition of rotation of the rotary electric machine21is complete, then the controller22terminates re-actuation of the starter11. Then, the engine10is started by motoring actuation of the alternator20.

Theater, upon receipt of the signal for turning off the alternator motoring actuation command from the ECU30, “YES” is selected at step S204, and then the process flow proceeds to step S242. At step S242, the controller terminates motoring actuation of the alternator20. Thus, start-up of the engine is complete.

FIG. 6is a timing diagram of engine start-up control.FIG. 6illustrates a scenario where the engine10is automatically stopped and then restarted.

The engine10is stationary before time t11. At time t11, an engine start-up request for starting the engine10is generated in response to a driver action. More specifically, the engine start-up request may be generated in response to acceleration or braking cancellation by the driver. Upon initial start-up of the engine10, the engine start-up request may be generated in response to a driver's key operation.

When the starter actuation command is generated in the ECU30in response to the engine start-up request, the starter11is activated. The rotary shaft13of the engine10rotates as the starter11is actuated. The alternator20is rotated by rotation of the rotary shaft13of the engine10. Thereafter, at time t12just before the TDC is reached, the starter actuation command is turned off and then the alternator motoring actuation command is generated. When motoring actuation of the alternator20is permitted by the alternator motoring actuation command, the controller22carries out the recognition of rotation of the rotary electric machine21.

Unless, under a condition where motoring actuation of the alternator20is permitted by the alternator motoring actuation command, the recognition of rotation of the rotary electric machine21is complete, the starter actuation command is generated again at time13, thereby activating the starter11again. Re-actuation of the starter11allows the pinion rotational speed NP to rise again and allows the pinion12and the ring gear14to mate with each other, which can prevent reduction in the engine speed NE. At time t13, the combustion control is activated. More specifically, the first fuel injection is carried out in a compression process just before the first coming combustion process after re-activation of the starter11, thereby providing combustion in this combustion process.

At time t14during re-actuation of the starter11, the controller22determines that the recognition of rotation of the rotary electric machine21is complete, in response to which the starter deactivation signal is generated and transmitted to the ECU30. Upon the ECU30receiving the starter deactivation signal, the starter actuation command is turned off and the starter11is thereby deactivated at time t15. A time period of t14to t15is a delay caused by communications between the ECU30and the controller22.

After time t15, engine start-up is carried out by actuation of the alternator20alone. A drive torque of the alternator20and a combustion torque generated in the combustion process allow the engine speed NE to rise.

When the engine speed NE reaches the threshold TH1at time t16, the signal for turning off the alternator motoring actuation command is transmitted form the ECU30to the controller22. Motoring actuation of the alternator20is thus terminated.

The present embodiment configured as above can provide the following advantages.

In the configuration set forth above, the controller22is configured to, under a condition where the engine rotary shaft13is rotating after deactivation of the starter11, determine whether or not recognition of rotation of the rotary electric machine21is complete, and if it is determined that recognition of rotation of the rotary electric machine21is not complete, carry out predefined fail-safe processing responding to an operating abnormality in the alternator20. With this configuration, determining that the recognition of rotation of the rotary electric machine21is not complete, under a condition where, after deactivation of the starter11, the alternator20is being rotated by rotation of the rotary shaft13, indicates that there is an abnormality in the alternator20. Carrying out the predefined fail-safe processing in such an event allows a rapid response to an operating abnormality in motoring actuation of the alternator20. With this configuration, an abnormality in the alternator20can be appropriately detected, which can prevent deterioration of engine start-up performance.

More specifically, in the fail-safe processing, a signal for re-actuating the starter11is outputted to the ECU30, thereby triggering the ECU30to re-actuate the starter11. In such an event, re-actuating the starter11can increase the engine speed NE again even if the engine speed NE has reduced after the last deactivation of the starter11. Therefore, even if initiation of motoring actuation of the alternator20is delayed from the last deactivation of the starter11, the engine10can advantageously be started.

In addition, the ECU30is configured to re-actuate the starter11and initiate fuel injection of the engine10. With this configuration, not only a drive torque of the starter11, but also a combustion torque of the engine10can be applied to the engine rotary shaft13. Therefore, even in the event there is a failure in the alternator20, the engine10can be started.

Under a condition where the alternator20is being rotated by rotation of the rotary shaft13, if a rotating state of the rotary electric machine21is detected and if a phase to be excited for motoring actuation of the alternator20is detected, then the motoring actuation of alternator20is initiated. In this confutation, therefore, if at least one of the rotating state of the rotary electric machine21and the phase to be excited for motoring actuation of the alternator20is not detected, then it is determined that the recognition of rotation is not complete, which triggers the starter11to be re-actuated. With this configuration, a status of recognition of rotation of the rotary electric machine21can be appropriately detected, which allows a rapid response to deterioration of engine start-up performance caused by an operating abnormality in the alternator20.

In the configuration set forth above, if, after re-activation of the starter11, it is determined that recognition of rotation of the rotary electric machine21is not complete, then the alternator20is deactivated, more specifically, the motoring actuation command for the alternator20is turned off. In the event, after re-activation of the starter11, it is determined that recognition of rotation of the rotary electric machine21is not complete, there may be a failure in the alternator20. In the presence of such a failure, even if the motoring actuation command for the alternator20is continued, motoring actuation of the alternator20is less likely to be initiated. Energy consumptions can therefore be suppressed by turning off the motoring actuation command for the alternator20.

Modifications

There will now be described some modifications that may be devised without departing from the spirit and scope of the present invention.

(M1) In the embodiment set forth above, the ECU30is configured to, upon receipt of the re-actuation signal for re-actuating the starter11, re-actuate the starter11and initiate fuel injection using the fuel injection valve (at steps S123, S124ofFIG. 4.). Alternatively, the fuel injection timing after initiation of the engine start-up may be changed. For example, the ECU30may be configured to, if, after re-activating the starter11, it is determined that the recognition of rotation of the alternator20is not complete, then initiate the fuel injection of the engine10before re-actuation of the starter11is terminated. More specifically, the ECU30may be configured to, if it is determined that the recognition of rotation of the alternator20is not complete within a time period after re-activation of the starter11, initiate the fuel injection of the engine10. That is, inFIG. 4, “NO” is selected at step S131and the fuel injection of the engine10is initiated upon expiration of the predetermined time period.

Normally, the fuel injection of the engine10is initiated after deactivation of the starter11. In such an alternative embodiment, the fuel injection of the engine10is initiated before termination of re-actuation of the starter11. If it is determined that recognition of rotation of the alternator20is not complete even after re-activation of the starter11, it is likely that there is a failure in the alternator20. In such an event, initiating the fuel injection of the engine10at an earlier time allows the engine speed NE to be increased by a drive torque of the starter11and a combustion torque of the engine11, thereby preventing deterioration of engine start-up performance.

(M2) In the embodiment set forth above, if the rotating state of the rotary electric machine21and the phase to be excited for motoring actuation of the alternator20are both detected (at steps S205, S206), then it is determined that the recognition of rotation of the rotary electric machine21is complete. Additionally or alternatively, if the rotating state of the rotary electric machine21and the phase to be excited for motoring actuation of the alternator20are both detected and if initiation of motoring actuation of the alternator20is detected, then it may be determined that the recognition of rotation of the rotary electric machine21is complete. The determination as to whether or not motoring actuation of the alternator20has been initiated may be determined based on whether or not current control of the rotary electric machine21has been initiated synchronously with the phase in the rotational drive24.

In such an embodiment, if the rotating state of the rotary electric machine21and the phase to be excited for motoring actuation of the alternator20are both detected and if initiation of motoring actuation of the alternator20is detected, then the engine10may be started by motoring actuation of the alternator20without re-actuating the starter11. If at least one of the rotating state of the rotary electric machine21and the phase to be excited for motoring actuation of the alternator20is not detected or if initiation of motoring actuation of the alternator20is not detected, it may be determined that that the recognition of rotation of the rotary electric machine21is not complete. Then the re-actuation signal for the starter11may be transmitted (as in step S211).

(M3) In the embodiment set forth above, if the ECU30receives the starter deactivation signal during re-actuation of the starter11(at step S131), the ECU30deactivate the starter11(at step S132). Alternatively, the ECU30may be configured to, at a predefined deactivation time after receipt of the starter deactivation signal, deactivate the starter11. In such an embodiment, an additional step at which the ECU30determines a timing of deactivation of the starter11after receipt of the starter deactivation signal may be inserted between steps S131and S132ofFIG. 4. The ECU30may be configured to determine whether or not the position of the engine10is a predefined position just before top dead center (TDC), as in step S112.

(M4) In the embodiment set forth above, the re-actuation signal for re-actuating the starter11is transmitted from the controller22to the ECU30, and then the ECU30re-actuates the starter11. Alternatively, the controller22may be configured to re-actuate the starter11. In such an embodiment, no communications between the controller22and the ECU30that may cause a delay of deactivation the starter11are not required, which allows more rapid re-actuation of the starter11.

(M5) In the embodiment set forth above, actuation time periods of the starter11and the alternator20do not overlap. Alternatively, the actuation time periods of the starter11and the alternator20may overlap. The ECU30may be configured to simultaneously generate the starter actuation command and the alternator motoring actuation command, or may be configured to, during the starter actuation command being ON, generate the alternator motoring actuation command. In such an embodiment, within a predetermined time period after the starter actuation command is turned off, it may be determined whether the recognition of rotation of the rotary electric machine21is complete in the controller.

(M6) In the embodiment set forth above, the engine10is started by using both the DC starter11and the AC alternator20. Alternatively, the engine10may be started by using two AC starters. In such an embodiment, the two AC starters may be a high-power and a low-power AC starter, where the high-power AC starter is actuated first and the low-power AC starter is actuated subsequently.

(M7) In the embodiment set forth above, the alternator20used as the engine start apparatus contains no engine speed sensor. Alternatively, the alternator20used as the engine start apparatus may contain an engine speed sensor.