JP2010025055A - Alternator control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alternator control device and an alternator control method capable of controlling motions of an alternator at the starting of an engine at optimal timing in consideration of environmental temperature and surely improving starting capability of the engine regardless of the environmental temperature. <P>SOLUTION: Power generation of the alternator 3 is stopped until the number of rotation Ne of the engine 1 reaches a setting value Ns at the starting of the engine 1. Especially, the number of rotation Ne of the engine 1 is compensated in a direction where the setting value Ns is increased in proportion as cooling water temperature Tw becomes lower. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an alternator for a vehicle having an alternator that generates power by receiving power from an engine and a battery that is charged by the output of the alternator.

  A vehicle such as an automobile has an alternator that generates power by receiving the power of the engine, and a battery that is charged by the output of the alternator. The battery is charged while the engine is running to prevent the battery from being consumed.

  In such an automobile, since the alternator starts a power generation operation as the engine starts, the alternator becomes a heavy load for starting the engine, and as shown in FIG. There is a problem of getting worse.

On the other hand, there is one that stops the power generation of the alternator until the fuel injection amount increases immediately after the engine is started or until the air-fuel efficiency feedback control is started after the engine is started (for example, Patent Document 1). If the alternator stops generating power, the engine load will be reduced and the engine startability will be improved.
JP 2004-72874 A

  However, as described above, the control for stopping the power generation of the alternator while considering the fuel injection amount and the air fuel efficiency feedback control has a major purpose of improving the fuel efficiency. In some cases, such as when the ambient temperature is low, the alternator starts generating electricity before the engine speed increases sufficiently, and eventually the startability of the engine may deteriorate. Further, in the self-ignition type engine, it is necessary to immediately energize electrical components involved in combustibility, and there is a risk that the load on the battery will increase if power generation of the alternator is stopped until air-fuel efficiency feedback control is started.

  The present invention takes the above circumstances into consideration, and its purpose is to control the operation of the alternator at the time of starting the engine at an optimum timing in consideration of the environmental temperature. An alternator control device and an alternator control method capable of reliably improving the performance and reducing the battery load at the time of starting.

  An alternator control device according to a first aspect of the present invention, in a vehicle having an alternator that generates electric power by receiving engine power, detects a rotational speed detection means for detecting the rotational speed of the engine, and detects a temperature of cooling water of the engine. Cooling water temperature detecting means, first control means for suppressing power generation of the alternator until the detected rotational speed of the rotational speed detecting means reaches a set value when the engine is started, and the set value of the first control means And second control means for correcting the temperature according to the detected temperature of the cooling water temperature detecting means.

  According to the alternator control device and the alternator control method of the present invention, it is possible to control the operation of the alternator at the time of engine start at an optimum timing in consideration of the environmental temperature. As a result, the startability of the engine can be reliably improved regardless of the environmental temperature, and the battery load at the start can be reduced.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, a starter 2, an alternator 3, and a rotation speed sensor 4 as a rotation speed detection unit are attached to an engine 1 of an automobile. Further, a cooling water temperature sensor 5 is provided as a cooling water temperature detecting means for detecting the temperature of the cooling water of the engine 1. The starter 2 operates by the voltage of the battery 6 and starts the engine 1. The alternator 3 generates power upon receiving the power of the engine 1 and charges the battery 6 with this power generation output.

  The starter 2, alternator 3, rotation speed sensor 4, coolant temperature sensor 5, ignition key switch (IG key SW) 11, and the like are connected to an ECU (Engine Control Unit) 10 that is a control unit.

  As shown in FIG. 2, the alternator 3 includes a stator coil 21 that generates a three-phase AC voltage due to magnetic field fluctuations, a field coil 22 that rotates by receiving power from the engine 1, and a three-phase AC voltage generated in the stator coil 21. A diode bridge 23 that rectifies the current, three diodes 24 for preventing backflow provided in a current path between the output terminal of the diode bridge 23 and the battery 6, and a current path between the diode 24 and the battery 6. An IC regulator 25 and the like provided in an energization path extending to the field coil 22 are included. The IC regulator 25 supplies an excitation current of an arbitrary level to the field coil 22 by driving a built-in switching element with an on / off duty according to a command from the ECU 10.

The ECU 10 has the following (1) to (3) as main functions.
(1) Control means for starting the engine 1 by operating the starter 2 when the ignition key switch 11 is turned on.

  (2) When the detected temperature Tw of the cooling water temperature sensor is equal to or lower than the predetermined value Tc when the engine 1 is started, the control for suppressing the power generation of the alternator 3 until the detected rotational speed Ne of the rotational speed sensor 4 reaches the set value Ns. Means (first control means). Specifically, at the time of starting the engine 1, the operation of the IC regulator 25 of the alternator 3 is suppressed when the detected rotational speed Ne is less than the set value Ns, and the IC of the alternator 3 is controlled when the detected rotational speed Ne exceeds the set value Ns. The suppression of the operation of the regulator 25 is released.

  (3) Control means (second control means) for correcting the set value Ns according to the detected temperature Tw of the coolant temperature sensor 5. Specifically, the set value Ns is corrected to increase as the detected temperature Tw is lower.

Next, the operation of the above configuration will be described with reference to the flowchart of FIG.
When the driver turns on the ignition key switch 11, the starter 2 is operated by the voltage of the battery 6, and the engine 1 is started.

  At this time, as the ignition key switch 11 is turned on (YES in Step 101), the coolant temperature Tw of the engine 1 is detected by the coolant temperature sensor 5 (Step 102). At this time, if the coolant temperature Tw is equal to or lower than the predetermined value Tc (YES in step 103), the set value Ns for the rotational speed Ne is corrected according to the detected temperature Tw (step 104). That is, if the detected temperature Tw is in a state of extremely low temperature or less, a value higher than a predetermined value is selected as the set value Ns, and if the detected temperature Tw is higher than the extremely low temperature, the predetermined value is set to the set value Ns. Selected as Note that the set value Ns selected when the detected temperature Tw is at or below the cryogenic temperature may be a value that is higher by an amount corresponding to the temperature difference between the detected temperature Tw and the cryogenic temperature.

  On the other hand, the rotational speed Ne of the engine 1 is detected by the rotational speed sensor 4 (step 105), and the detected rotational speed Ne is compared with the corrected set value Ns (step 106).

  In this comparison, if the detected rotational speed Ne is still less than the set value Ns immediately after starting (NO in step 106), the on / off duty “0”% is commanded from the ECU 10 to the alternator 3. In accordance with this command, the ON / OFF duty of the switching element of the IC regulator 25 is set to “0”%. That is, the operation of the IC regulator 25 is suppressed and no exciting current is supplied from the IC regulator 25 to the field coil 22 (step 107). In the above embodiment, “0”% is set as the on / off duty for the alternator 3, but the on / off duty value is not limited and may be set appropriately to such an extent that the startability of the engine is not deteriorated. That's fine.

  By suppressing the exciting current to the field coil 22, the magnetic field from the field coil 22 is suppressed, and even if the field coil 22 is rotated by the power of the engine 1, the three-phase AC voltage generated from the stator coil 21. Is suppressed or not generated.

  Thereafter, when the detected rotational speed Ne increases and reaches the set value Ns (YES in Step 106), the ECU 10 determines whether the engine 1 has sufficiently increased and the engine 1 has reached a complete explosion state. For example, on / off duty “50”% is commanded to 3. In accordance with this command, the ON / OFF duty of the switching element of the IC regulator 25 is set to “50”%. That is, the suppression of the operation of the IC regulator 25 is released by the voltage of the battery 6, and a predetermined level of exciting current is supplied from the IC regulator 25 to the field coil 22 (step 108).

  When a predetermined level of exciting current is supplied to the field coil 22, a sufficient magnetic field is generated from the field coil 22, and the battery coil 6 has a level sufficient to charge the battery 6 from the stator coil 21 by rotating the field coil 22. A three-phase AC voltage is generated. This three-phase AC voltage is rectified by the diode bridge 23 to become a DC voltage, which is supplied to the battery 6 and the IC regulator 25.

  Thereafter, the operation of the engine 1 and the power generation of the alternator 3 are continued, and the battery 6 is charged by the output of the alternator 3.

  As described above, when the engine 1 is started, power generation of the alternator 3 is suppressed until the rotational speed Ne of the engine 1 reaches the set value Ns. Therefore, the alternator 3 does not become a load on the engine 1 and the startability of the engine 1 is improved. Is done.

  In particular, since the set value Ns is corrected to be higher as the coolant temperature Tw is lower, power generation of the alternator 3 can be started at an optimal timing when the engine speed has sufficiently increased. Therefore, the startability of the engine 1 can be reliably improved regardless of the environmental temperature.

  Further, when the coolant temperature Tw at the time of starting the engine exceeds the predetermined value Tc, the power generation suppression control by the alternator by the first control means is not performed. That is, in a situation where the environmental temperature is not low and the engine speed rises smoothly, power generation of the alternator 3 and charging of the battery 6 are started immediately including the cranking period. Thereby, the battery 6 can be charged early while ensuring good startability of the engine 1.

  In the above embodiment, “50”% is set as the on / off duty of the switching element of the IC regulator 25 when power generation of the alternator 3 is started. However, the value of the on / off duty is not limited, and the alternator The power generation capacity of 3 or the capacity of the battery 6 may be set as appropriate. In addition, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention.

The block diagram which shows the structure of one Embodiment of this invention. The block diagram which shows the electric circuit of the alternator in the embodiment. The flowchart for demonstrating the effect | action of the embodiment. The figure which shows the mode of the raise of the conventional engine rotation.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Starter, 3 ... Alternator, 4 ... Speed sensor, 5 ... Cooling water temperature sensor, 6 ... Battery, 10 ... ECU (control part), 11 ... Ignition switch, 21 ... Stator coil, 22 ... Field Coil, 23 ... Diode bridge, 25 ... IC regulator

Claims (4)

In a vehicle having an alternator that generates power by receiving engine power,
A rotational speed detection means for detecting the rotational speed of the engine;
Cooling water temperature detecting means for detecting the temperature of the cooling water of the engine;
First control means for suppressing power generation of the alternator until the detected rotational speed of the rotational speed detection means reaches a set value when the engine is started;
Second control means for correcting the set value of the first control means in accordance with the detected temperature of the cooling water temperature sensor;
An alternator control device comprising:   2. The alternator control device according to claim 1, wherein the second control unit corrects the setting value so as to increase as the detected temperature of the cooling water temperature detection unit decreases.   3. The alternator control device according to claim 1, wherein the first control unit cancels suppression of power generation when a detected temperature at the time of starting the engine is equal to or higher than a predetermined value. 4. The alternator has a regulator for supplying an exciting current for power generation,
The first control means stops the operation of the regulator when the engine is started and the rotation speed detected by the rotation speed detection means is less than a set value, and the rotation speed detected by the rotation speed detection means is greater than or equal to a set value. Then, the regulator is operated.
The alternator control apparatus according to claim 1 or 2, wherein

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