JP2003184715A - Automatic engine stop and restart device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic engine stop and restart device capable of improving engine acceleration in engine restart under economy running control while suppressing specification changes in an existing starter motor to a minimum. <P>SOLUTION: Motor starting torque in automatic engine restart is controlled to be smaller than motor starting torque in engine manual start buy turning an ignition key on. For example, a part of a series field winding 11 of an engine starter motor 1 is shorted to reduce magnetic flux by turning on a short circuit relay 7 in automatic engine restart. Consequently, motor characteristics are changed to low-starting torque type (high speed type) characteristics. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic engine stop / restart system, and more particularly to an automatic engine stop / restart system for changing the characteristics of a starter motor between manual start and automatic restart.

[0002]

2. Description of the Related Art In recent years, for the purpose of improving fuel efficiency and reducing emissions, an automatic engine stop command is issued when a predetermined engine stop condition is satisfied, and an automatic engine restart is performed when a predetermined engine start condition is satisfied thereafter. Engine automatic stop and restart control (so-called eco-run control) that commands the start and drives the engine start motor
Is being adopted. As this engine starting motor, that is, a starter motor, a DC direct winding motor that can obtain a large starting torque is usually adopted.

An important point in this eco-run control (also called idle stop control) is that automatic engine restart is performed when the vehicle is started, so that the engine speed is raised as quickly as possible to a speed at which the vehicle start torque can be generated. There is one point. If the engine is automatically restarted and it takes time, the driving feeling of the eco-run vehicle will be significantly reduced.

In order to solve this problem, in the conventional eco-run vehicle, the starting torque has been increased by increasing the output of the starter motor.

However, such an increase in the size of the starter motor has a problem in that the space for the engine is narrowed in addition to the increase in the cost, and an adverse effect is caused by the increase in the number of models of the starter motor to be manufactured.

The present invention has been made in view of the above problems, and it is possible to improve engine acceleration at the time of automatic restart of the engine in the eco-run control while suppressing the specification change of the existing starter motor to the minimum. Its purpose is to provide a stop-restart device.

[0007]

An engine automatic stop / restart system according to a first aspect of the present invention includes an engine starting motor having at least a series winding field winding, and an automatic engine stop command when a predetermined engine stop condition is satisfied. An engine automatic stop / restart system comprising: an engine automatic stop / restart control unit for instructing an engine automatic restart to drive the engine start motor when a predetermined engine start condition is satisfied thereafter; It is characterized in that it has a motor characteristic control unit for reducing the motor starting torque at the time when compared with the motor starting torque at the time of manual starting.

That is, the automatic engine stop / restart system of the present invention controls the motor starting torque at the time of automatic engine restart to be smaller than the motor starting torque at the time of manually starting the engine by turning on the ignition key. It has a feature. The DC series-wound motor most widely used as a starter motor has a motor characteristic of a low starting torque type (high rotation type) by reducing the amount of field flux by, for example, reducing the number of turns of the series winding field winding. If changed, if the current is constant, the rotation speed increases and the torque decreases.

The acceleration of the engine at the time of automatic engine restart is proportional to the torque difference (acceleration torque) obtained by subtracting the load torque (the engine is the load) viewed from the starter motor from the torque generated by the starter motor at a certain rotation speed. . Therefore, if this torque difference (acceleration torque) is integrated from the engine speed 0 to a predetermined value (a rotation value that allows the engine to generate a torque sufficient for self-acceleration by itself), the engine speed is changed from 0 to this predetermined value. The time required for lifting is obtained.

A torque difference (acceleration torque) obtained by subtracting the load torque (the engine is the load) seen from the starter motor from the torque generated by the starter motor in the entire rotation speed range at the time of starting the engine by using a very large motor
Is set to be sufficiently large, which is best, but this is not possible in terms of cost, storage space and vehicle weight.

Therefore, in a normal starter motor, the torque-rotational speed characteristic of the starter motor is set to a large value so that the motor has a motor starting torque that can reliably start the engine even at cold start when the engine temperature is low and the friction is large. Designed as a torque type (low rotation type).

In a DC series-wound motor, an increase in starting torque can be realized by an increase in the amount of field flux due to an increase in the number of turns of the series winding field winding. However, such an increase in the amount of field flux is due to an increase in the back electromotive force of the armature winding, which is proportional to the product of the number of revolutions and the amount of field flux, increases in the low engine speed region, and the current and the amount of field flux are correspondingly increased. It means that a decrease in torque proportional to the current and the amount of field magnetic flux occurs early in this low engine speed region. That is, in the conventional DC direct-winding motor type starter motor, the peak of the motor output must be ensured in order to ensure a large motor starting torque that enables cold start of the engine within the motor output range limited by the motor size. There was no choice but to lean toward the low rotation side, and after the engine started to rotate, the torque decreased early,
After that, I had to accept the phenomenon that it took time to increase the engine speed to the required value. At the first manual start, such a delay in engine start-up is not a problem, but when the engine is automatically restarted after starting after idling stop in eco-run control, the driver has already stepped on the accelerator. People are sensitive to vehicle start acceleration, and delay in automatic engine restart is a starter motor performance that requires improvement.

Therefore, in the present invention, the large starting torque type (low rotation type) motor characteristic is used as in the conventional case at the manual start, and the automatic engine restart at the start after the idle stop in the eco-run control is performed as follows. For example, the motor characteristic is changed to a low starting torque type (high rotation type) by reducing the amount of field magnetic flux by reducing the number of turns of the series winding field winding. In this way, since the field magnetic flux amount is reduced and the back electromotive force of the armature winding can be reduced compared to the case of the previous large starting torque type (low rotation type) motor characteristic, it is possible to increase to a high rotation speed range. Since the torque can be secured, it is possible to improve the increasing speed of the engine speed after starting the engine rotation (to be precise, after overcoming the first load torque peak thereafter), which is good for the driver. A start response can be given.

It should be noted that the adoption of such a low starting torque type (high rotation type) motor characteristic in the automatic engine restart at the time of starting after the idle stop naturally causes a decrease in the motor starting torque of the starter motor. However, when the engine is automatically restarted immediately after the vehicle stops running, the lubricating oil whose viscosity has been reduced due to friction and heat generated by the engine is distributed to various parts of the engine, resulting in less friction loss and a large amount such as during a cold start. Even if the motor starting torque is not generated, the start failure does not occur.

The predetermined condition means that the engine temperature is within a predetermined temperature range suitable for starting the engine.

In a preferred mode, the motor characteristic control section has a short-circuit means for short-circuiting a part of the series-wound field winding, and the short-circuit means is turned on when the engine is automatically restarted to turn the series-winding coil on. Since a part of the field winding is short-circuited and the short-circuiting means is turned off to stop the short-circuiting when the engine is manually started, the above effect can be realized with a simple configuration.

In a preferred mode, the motor characteristic control unit prohibits the short circuit when the engine is automatically restarted when the engine temperature is equal to or higher than a predetermined value. This can improve the vehicle start response when the engine temperature is high. More specifically, when the engine temperature becomes higher than a predetermined value, the friction loss rather increases due to factors such as a reduction in clearance due to differences in the coefficient of thermal expansion between engine parts, and a large motor starting torque is required. According to this aspect, this problem can be solved.

The engine automatic stop / restart system of the second invention issues two engine starting motors and an automatic engine stop command when a predetermined engine stop condition is satisfied, and an engine automatic restart when a predetermined engine start condition is satisfied thereafter. In the engine automatic stop and restart device including an engine automatic stop and restart control unit that drives the engine start motor by instructing the above, one or both of the engine start motors is used at the time of manual start, and when the engine automatic restart is performed. By using the other of the both engine starting motors, a motor characteristic control unit for reducing the total motor starting torque at the time of automatic restart of the engine under a predetermined condition from the total motor starting torque at the time of manual starting is characterized. There is.

That is, according to the present invention, at the time of manual starting and automatic restart of the engine, at the time of manual starting requiring a large motor starting torque, the engine starting motor having the larger motor starting torque is used, or both of them are used. When the engine is started using the engine starting motor and the engine can be started with a relatively small motor starting torque, the engine starting motor with the smaller motor starting torque is used, so the configuration is slightly complicated, but The same effect as one invention can be exhibited.

A system using such two engine starting motors is designed to improve the reliability of the engine automatic stop / restart system. Then, there is an advantage that the above-mentioned effect can be realized without adding a circuit.

In a preferred mode, the torque-rotational speed characteristic of the other of the two engine starting motors at the time of automatic engine restart is set to a large motor starting torque generation type at least at the beginning of the automatic engine restart period under a predetermined condition, A small motor starting torque generation type is adopted in the latter half of the engine automatic restart period.

With this arrangement, the time required for automatic engine restart can be further shortened and the driving feeling can be improved.

An engine automatic stop / restart system according to a third aspect of the present invention includes an engine starting motor capable of changing a torque-rotational speed characteristic, an automatic engine stop command when a predetermined engine stop condition is satisfied, and a predetermined engine start condition thereafter. In an engine automatic stop / restart system including an engine automatic stop / restart control unit for instructing an engine automatic restart at the time of establishment to drive the engine start motor, the torque-rotation speed characteristic of the engine start motor is set to at least a predetermined condition. The large motor starting torque generation type is set at the beginning of the engine automatic restart period in the above, and the small motor starting torque generation type is set at the latter stage of the engine automatic restart period.

With this configuration, after the engine is started with a large torque at the beginning of the automatic engine restart period, the torque-rotational speed characteristic is switched to the high rotation type, so that the large engine is also started in the latter period of the automatic engine restart period. Since the acceleration can be realized, the time required for the automatic engine restart can be further shortened and the driving feeling can be improved.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a vehicular synchronous motor device of the present invention will be described with reference to the following embodiments.

[0026]

Embodiment 1 FIG. 1 shows an engine starting device, 1 is an engine starting motor composed of a direct current winding motor, 2 is a magnet switch, 3 is a relay, 4 is an ignition switch, 5 is a controller, 6 is a battery, and 7 is a battery. This is a short circuit relay, and the engine starting motor 1 comprises a series winding field winding 11 with an intermediate tap 10 and an armature coil (armature) 12 connected in series. The pair of contacts of the short-circuit relay 7 are individually connected to both ends of the main part of the series winding field winding 11 and turned on to short-circuit the main part of the series winding field winding. The configuration of the engine starting device itself includes a short circuit relay 7 and an intermediate tap 1.
It is the same as the existing one except 0.

That is, when the ignition switch 4 is turned on and the relay 3 is closed, the magnet switch 2
Is closed and the direct current winding motor 1 is energized from the battery 6,
The DC series-wound motor 1 is started by the large motor starting torque. Further, the controller 5 determines whether or not the engine can be automatically stopped and the automatic restart thereafter based on an input signal from a sensor or the like. In the case of the automatic engine restart, the short circuit relay 7 is closed and then the magnet switch 2 is energized. As a result, the direct current winding motor 1 is started with a small motor starting torque. The control operation at the time of automatic restart of the engine by the controller 5 will be described below with reference to the flowchart of FIG.

First, it is determined whether the engine is automatically stopped by the eco-run (100), and if the engine is automatically stopped, it is determined whether the engine automatic restart condition is satisfied (102). Is closed, the relay 3 is closed, and the magnet switch 2 is energized to start the DC series-wound motor 1 with a small motor starting torque (104). Next, it is determined whether the automatic engine restart is completed based on an input signal such as the engine speed (106). When the automatic engine restart is completed, the relay 3 is opened and the relay 7 is opened (108). Return to the main routine.

According to this embodiment described above, the effects described above can be obtained, and the engine acceleration performance at the time of automatic restart of the engine in the eco-run control can be suppressed while suppressing the specification change of the existing starter motor to the minimum. An engine automatic stop / restart device that can be improved can be realized.

[0030]

Second Embodiment Another embodiment of the present invention will be described below with reference to FIG.

In this embodiment, the short circuit relay 7 of FIG. 1 is replaced with a short circuit transistor 8 and a flywheel diode 9. The other circuit configuration is the same as that of FIG.

When the automatic restart of the engine is decided, the controller 5 closes the magnet switch 2 and starts the DC series-wound motor 1. After a predetermined short time has elapsed from the start-up time (preferably after the engine has rotated once or twice), the relay 7 is closed to reduce the amount of field flux and change the DC series-wound motor 1 to a high rotation type. As a result, the time required for automatic engine restart can be further shortened.

[0033]

Third Embodiment Another embodiment of the present invention will be described below with reference to FIG.

This embodiment is an example in which two engine starting motors are provided, and the engine 21 is a first engine starting motor 22 composed of a DC series-wound motor similar to that of the first embodiment.
The second engine starting motor 23 is a field winding type synchronous machine that operates as a generator motor.

The first engine starting motor 22 is directly connected to the engine 21 through a ring gear pinion connection (not shown). The second engine starter motor 23 generates an electric torque by controlling a normal Lander-pole type AC generator through a three-phase inverter circuit that also functions as a rectifier, and gives this electric torque to the engine 21 through the belt 24. The engine can be started by.

In this embodiment, the engine starting motors 22 and 23 are designed so that when the engine is automatically restarted, the engine starting motors 22 and 23 both generate a torque that enables automatic engine restart. Thus, even if one of the engine starting motors fails, the other engine starting motor is driven, so that the automatic engine restart does not fail. Further, when the engine is cold-started (when manually started) by turning on the ignition switch 4, both engine starter motors 22 and 23 are simultaneously driven. As a result, a large torque can be applied to the engine, and cold start of the engine becomes possible. By doing so, the engine starting motor 22 corresponding to a normal engine starting motor can be designed to be a small motor starting torque type (high rotation type), and the time required for automatic engine restart at the time of automatic engine restart can be reduced. It can be shortened. In addition, although the structure seems to be complicated in this embodiment, it is only necessary to add an inverter circuit so that the existing AC generator can be electrically driven, and torque assist can be realized while traveling, so that fuel consumption can be improved. Can be expected.

(Modification) Various modifications can be considered to this embodiment, for example, the engine starting motor 2
2 is dedicated to cold start in order to reduce wear of the brush, and the engine starting motor 23 is dedicated to automatic engine restart,
If the engine starting motor 23 fails during automatic engine restart, the engine starting motor 22 may temporarily be able to automatically restart the engine. Further, in the automatic engine restart by the engine starting motor 22, the direct winding field winding may be partially short-circuited, or after a predetermined short time has elapsed from the start of the automatic engine restart, as in the second embodiment. You may short-circuit a part of series winding field winding.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an engine automatic stop / restart system according to a first embodiment.

FIG. 2 is a flowchart showing an engine automatic restart control operation in FIG.

FIG. 3 is a circuit diagram showing an engine automatic stop / restart system according to a second embodiment.

FIG. 4 is a block diagram showing an engine automatic stop / restart system according to a third embodiment.

[Explanation of symbols]

1 Engine starting motor (DC direct winding motor) 7 Short-circuit relay 11 Series winding field winding

Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02N 15/00 F02N 15/00 E (72) Inventor Keizo Takamatsu 1-1, Showa-cho, Kariya city, Aichi Prefecture DENSO CORPORATION F term (reference) 3G092 AA01 AB02 AC03 DF05 DG08 EA01 FA03 GA01 HF05X HF19Z 3G093 AA01 BA21 BA22 CA02 CB05 EC02 FB02

Claims (6)

[Claims] 1. An engine starting motor having at least a series winding field winding, an automatic engine stop command when a predetermined engine stop condition is satisfied, and an automatic engine restart command when a predetermined engine start condition is satisfied thereafter. In an engine automatic stop / restart system including: an engine automatic stop / restart control unit for driving the engine start motor to drive the engine start motor, a motor starting torque at the engine automatic restart under a predetermined condition is calculated from a motor starting torque at the manual start. An automatic engine stop / restart device having a motor characteristic control unit for reducing 2. The engine automatic-stop / restart device according to claim 1, wherein the motor characteristic control unit has a short-circuit means for short-circuiting a part of the direct-winding field winding, and when the engine is automatically restarted. An engine automatic stop / restart device, characterized in that the short-circuit means is turned on to short-circuit a part of the direct winding field winding, and the short-circuit means is turned off to stop the short-circuit when the engine is manually started. 3. The engine automatic stop / restart system according to claim 2, wherein the motor characteristic control unit prohibits the short circuit when the engine is automatically restarted when the engine temperature is equal to or higher than a predetermined value. Automatic engine stop / restart device. 4. Two engine starting motors and an engine automatic stop command when a predetermined engine stop condition is satisfied, and an engine automatic restart command when the predetermined engine start condition is satisfied thereafter to drive the engine start motor. An engine automatic stop / restart control unit including: an engine automatic stop / restart control unit, wherein one or both of the engine start motors are used during manual start, and the other of the engine start motors is used during engine automatic restart. Accordingly, the engine automatic stop / restart device is provided with a motor characteristic control unit that reduces the total motor starting torque at the time of automatic restart of the engine under a predetermined condition as compared with the total motor starting torque at the time of manual starting. 5. The engine automatic stop / restart system according to claim 4, wherein the torque-rotational speed characteristic of the other of the two engine starting motors at the time of the automatic engine restart is set to at least the engine automatic restart period at a predetermined condition. An automatic engine stop / restart system, characterized in that a large motor starting torque generation type is initially used and a small motor starting torque generation type is used in the latter half of the engine automatic restart period. 6. An engine starting motor capable of changing a torque-rotational speed characteristic, an automatic engine stop command when a predetermined engine stop condition is satisfied, and an automatic engine restart command when a predetermined engine start condition is satisfied thereafter. An engine automatic stop / restart control unit that drives the engine start motor, and an engine automatic stop / restart system comprising:
An automatic engine stop / restart system, wherein a large motor starting torque generation type is used at least in an early stage of the engine automatic restart period under a predetermined condition, and a small motor starting torque generation type is used in a latter period of the engine automatic restart period.