JPH03970A - Engine start device - Google Patents

Abstract

PURPOSE:To ensure good startability regardless of an engine condition by providing a starter motor with a bypass circuit for bypassing the field coil of the motor, and an open/close means for opening and closing the bypass circuit, and controlling the open/close means depending upon the detected result of an engine condition at the time of a start. CONSTITUTION:When a starter switch 1 is turned on, electric current flows from a battery 2 to the attraction coil 4 of a magnetic switch 3 and a retaining coil 5, thereby generating an attraction force. A pinion is pushed out with the attraction force and geared with a ring gear. At the same time, a main contact 10 is opened and current flows to a field coil 12, thereby generating magnetic field and turning a motor (armature) 11. In this case, a bypass circuit 21 for bypassing the field coil 12 is provided and a normally open relay 13 is provided in the circuit 21. The relay 13 is closed, for example, when an engine speed exceeds the predetermined number of revolutions in a cold engine condition for increasing the feed amount of current to the motor 11, thereby helping increase the engine speed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an engine starting device including an automobile starter motor.

<Prior Art> The engine that provides the driving force for an automobile cannot be started by its own blade, so it must be started by turning the crankshaft from the outside. For this purpose, a starter (starting device) is installed, and the main component of this starting device is a starter motor.

The starter motor is generally a DC series-wound type, and its output is determined by the rotational resistance of the engine and the minimum rotational speed that can be started, so that a sufficient rotational speed can be obtained even in winter. Examples of starter motors used in conventional engine starting devices include the one shown in Figure 7 (Sankairyo Co., Ltd. Published October 15, 1980 Automotive Engineering Complete Works Volume 10 Electrical Components, Body Equipment, Engines) (See Parts, pages 29 to 41, etc.).

That is, when the starter switch 1 is turned on, a current flows from the battery 2 to the attraction coil 4 and the holding coil 5 of the magnetic switch 3 in the direction of the arrow, generating a bow force. This suction force pushes out the pinion 7 via the shift lever 6 and engages it with the ring gear 8.

When the plunger 9 is moved by the attractive force, the main contact 10 of the magnetic switch 3 is closed, so that current flows from the plunger 2 to the field winding 12 to generate a magnetic field, and the motor (armature) 11 starts rotating.

Then, the torque of the motor 11 is transmitted to the ring gear 8 by the pinion 7 to start the engine.

<Problems to be Solved by the Invention> However, such a conventional engine starting device has characteristics as shown in FIG. In other words, if the magnetic flux density is set to be strong in order to obtain a large torque, the motor rotation speed will decrease, while if the magnetic flux density is set to be weak in order to increase the motor rotation speed, the output torque will be reduced. It has the characteristic that it cannot achieve both high torque and high torque.

For this reason, if the magnetic flux density is increased to emphasize torque in order to improve engine startability at room temperature, the crankshaft will not be able to reach a sufficient rotational speed when starting the engine, which will impede engine startability. We cannot secure enough. On the other hand, if the magnetic flux density is weakened to emphasize rotation speed, the output torque of the starter motor will be insufficient, and the crankshaft will not be able to rotate at a sufficient speed, especially in cold weather due to the viscosity of the engine oil. There was a problem in that the crankshaft could not be rotated at all during hot rest footing, when the rotational friction of the engine increased, or conversely, when the engine became hot.

The present invention was made in view of such conventional circumstances,
An object of the present invention is to provide an engine starting device that improves engine startability by detecting the state of an engine at the time of starting and controlling the switching of the output characteristics of a starter motor according to the engine state.

<Means for Solving the Problem> For this reason, the present invention provides a starter motor that generates a magnetic field by passing a current through a field winding to start an engine.
A bypass circuit for bypassing the field winding, a switching means for opening and closing the bypass circuit, an engine state detection means for detecting an engine state at the time of starting, and opening/closing control of the opening/closing means according to the engine state. The configuration includes a control means for

<Operation> The rotational torque of the starter motor increases in proportion to the magnetic flux, and the rotational speed increases in inverse proportion to the magnetic flux. However, according to the above configuration, the engine condition at the time of starting is detected and the engine The current flowing through the bypass circuit that bypasses the field winding is controlled according to the state.This allows for cases where engine rotational torque is required, such as when engine rotational friction is large, and when there is apparent engine rotational friction. Both a high rotational speed when the engine speed is low and a high rotational speed when the engine speed is required are ensured, and the engine can be started reliably.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a circuit configuration diagram when applied to a diesel engine as a first embodiment of the present invention.

First, the configuration will be explained. Components that are the same as those in the conventional example are given the same reference numerals as in FIG. 7, and their explanations will be omitted.

When the main contact 10 of the magnetic switch 3 closes,
A bypass circuit 21 is provided so that the current from the battery 2 flows to the motor 11 by bypassing the field winding 12, and a normally open relay is used as an opening/closing means for opening and closing the current flowing through the bypass circuit 21. 13 is interposed.

Here, as a configuration according to the first embodiment, the relay 13 is as follows:
Opening/closing control is performed by a control unit 16 which receives signals from a rotation sensor 14 that detects the number of rotations and a water temperature sensor 15 that detects the engine cooling water temperature.

Next, the operation will be explained according to the flowchart shown in FIG.

In step 1 (denoted as S in the figure, the same applies hereinafter), the starter switch 1 is turned on to start the engine.

In step 2, the control unit (I6) is turned on.

In step 3, the main contact 10 of the magnetic switch 3 is turned on, so the motor 11 starts rotating. still,
The motor 11 in this embodiment has an output setting that emphasizes torque by increasing the magnetic flux density so that when current flows through the field winding 12 in the step 3 state, the magnetic flux density is increased so that the engine starts easily at room temperature. ing.

In step 4, the measurement result T from the water temperature sensor 15 is input to the control unit I6, and in step 5, it is determined whether the temperature is higher or lower than a predetermined value (for example, 0°C and 60°C).

When the temperature T is low (less than 0° C.), it is assumed that the rotational friction of the engine is increasing due to the viscosity of the engine oil, etc., and the motor 11 is first rotated with the output setting emphasizing torque. Then, the process proceeds to step 6, where the rotational speed N of the motor or the rotational speed Ne of the engine is measured by the rotational sensor 14 and input to the control unit 16.

Then, in step 7, it is determined whether the rotational speed N (Ne) is higher or lower than a predetermined rotational speed (for example, 250 rpm), and if it is larger than the predetermined value, the process proceeds to step 8.
The relay 13 is activated and the relay contact is turned on. In other words, even at low temperatures (below 0°C), if the motor rotation speed or engine rotation speed becomes higher than the predetermined rotation speed (25 rpm), there is no need for high torque due to the increase in rotational friction. , field winding 1
By bypassing the motor 2, the current supplied to the motor 11 is increased, thereby increasing the rotational speed N.

On the other hand, in step 5, if the cooling water temperature T is high (for example, higher than 60"C) during a high-temperature restart, air may remain in the fuel injection valve (not shown).
In order to exhaust the air, it is necessary to frequently perform suction and exhaust, so the process proceeds to step 8, where the contact of the relay 13 is turned on and the rotational speed N is increased.

Furthermore, in step 5, if the cooling water temperature T is within a temperature range that is considered to be normal temperature (for example, 0°C≦T≦60°C), the engine startability is good, so normal motor 11 control is performed. Even if this is done, there is no problem in starting the engine, so a normal current is passed through the field winding 12 and the engine is started with the output setting emphasizing torque.

After starting the engine, the starter switch 1 is turned off in step 9, the operation of the control unit 1-16 is stopped in step 10, and then the series of operations is completed.

As explained above, the temperature, which is the engine state at the time of starting, is detected, and the field winding 12 is also detected based on the engine rotation speed.
Since the normally open relay 13, which serves as an opening/closing means, is controlled to open and close by flowing current to the bypass circuit 21 of the bypass circuit 21, as shown in Fig. As a result of complete combustion starting after the initial explosion, both the apparent engine rotational friction and high rotational speed are ensured, and the engine can be started reliably.

As explained above, diesel engines generally have a high compression ratio, so the rotational resistance of the engine is large.
Therefore, a starter motor that generates a large amount of torque is required. In addition, diesel engines will not start at extremely low temperatures unless the engine rotation is assisted until just before the engine completely explodes (approximately 450 rpm). When using a motor, it is difficult to start the engine because the rotational speed is insufficient when the engine rotational friction is small, but the engine starting device according to this embodiment detects the state of the engine at the time of starting. Since the starter motor output characteristics are switched and controlled according to the engine condition, the engine can be started reliably.

Next, as a second embodiment of the present invention, a case where the present invention is applied to a gasoline engine will be described. In addition, also in this example,
The circuit configuration is the same as the circuit configuration when applied to the diesel engine as the first embodiment described above, so
The explanation will be omitted, and the operation will be explained according to the flowchart shown in FIG. In addition, when explaining the flowchart, the same operations as those in FIG. 2 illustrating the operation of the first embodiment are given the same reference numerals, and the explanation thereof will be omitted.

In this embodiment, in step 21, if the engine cooling water temperature T is high (for example, higher than 60°C), the process proceeds to step 22, where the relay 13 is turned ON by a signal from the control unit 16, and the field By bypassing the winding 12, the current supplied to the motor 11 is increased, thereby increasing the rotational speed N.

That is, the cooling water temperature T is high at the time of a high-temperature restart (for example, 6
(higher temperature than 0°C), air intake and exhaust frequently to improve engine startability.

Furthermore, a gasoline engine can be started at a low rotational speed (approximately 8 rpm) at room temperature or low temperature, and unlike a diesel engine, there is no need to assist the rotation until complete explosion, so there is no need to control the motor rotational speed.

FIG. 5 shows the ON state of the relay 13 according to the motor rotation speed N in the first embodiment as a third embodiment of the present invention.
・OFF type [This is a circuit configuration diagram of an embodiment in which determination is made based on the terminal voltage of the pantry 2 instead of r.

First, the configuration will be explained. Components that are the same as those of the conventional example and the first embodiment are designated by the same reference numerals as in FIG. 1, and their explanations will be omitted.

When the main contact 10 of the magnetic switch 3 closes,
A bypass circuit 21 is provided so that current from the battery 2 flows to the motor 11 by bypassing the field winding 12, and a normally open relay 13 serves as an opening/closing means for opening and closing the current flowing through the bypass circuit 21. is interposed. Here, in the configuration according to the third embodiment, the terminal voltage (8) of the battery 2 inputted via the input circuit 23 and the signal from the water temperature sensor 15 that detects the engine cooling water temperature are inputted to the control unit 16. , the opening/closing control is performed by the control unit 16d.

Next, the operation will be explained according to the flowchart in FIG. 6. When explaining the flowchart, the same operations as those in FIG. 2, which illustrates the operation of the first embodiment, will be given the same reference numerals and the explanation thereof will be omitted.

In step 5, when the temperature T is low (below 0°C), it is assumed that the rotational friction of the engine is increasing due to the viscosity of the engine oil, etc., and the motor 11 is first rotated with the output setting that emphasizes torque. After being forced to do so, step 31
Then, the terminal voltage (8) of the battery 2 is input to the control unit 16.

Then, in step 32, the terminal voltage vIl is set to a predetermined voltage ■c
If it is higher or lower than the predetermined value, it is determined that the engine speed N is sufficiently large and the battery 2 is sufficiently charged, and the process proceeds to step 33, in which the relay 13 is activated and the relay is activated. Turn the contact ON. That is, even at low temperatures (below O''C0), if the terminal voltage (2) is higher than the predetermined voltage (2), the engine rotational speed N is sufficiently large, and there is no need for high torque due to the increase in rotational friction. For example, by bypassing the field winding 12, the current supplied to the motor 11 is increased, thereby further increasing the rotational speed N.

On the other hand, in step 5, if the cooling water temperature T is high (for example, higher than 60°C) at the time of high-temperature restart, etc., regardless of the magnitude of the terminal voltage V, step 33 is performed as in the case of the first embodiment. Then, the contact of the relay 13 is turned on and the rotational speed N is increased.

As explained above, in this embodiment as well, the temperature, which is the engine state at the time of starting, is detected, and the current flowing through the bypass circuit 21 of the field winding 12 is switched on and off based on the terminal voltage VIl of the battery 2. Since the normally open relay 13 as an opening/closing means is controlled to open and close, both high torque and high engine rotational speed are ensured, and the engine can be started reliably.

<Effects of the Invention> As explained above, according to the engine starting device of the present invention, the engine state at the time of starting is detected based on the engine cooling water temperature, the engine rotation speed, the battery terminal voltage, etc., and the motor load is determined. Since the engine is controlled so that a large torque is obtained when the load is high and a high rotational speed is obtained when the torque is low, the engine can be started reliably.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram according to a first embodiment and a second embodiment of the present invention, and FIG. 2 is a flowchart showing the operation of the same embodiment.
FIG. 3 is a performance characteristics explanatory diagram of a starter motor explaining the operation of the above embodiment, FIG. 4 is a flowchart showing the operation of the second embodiment of the present invention, and FIG. 5 is a diagram related to the third embodiment of the present invention. FIG. 6 is a flowchart showing the operation of the above embodiment, FIG. 7 is a circuit diagram of a conventional starter, and FIG. 8 is a diagram illustrating the performance characteristics of a starter motor to explain the problems of the conventional example. ■...Starter motor 11...Motor 12
... Field winding 13 ... Relay 14 ... Rotation sensor 15 ... Water temperature sensor 16 ... Control unit 21 ... Bypass circuit Patent applicant Nissan Motor Co., Ltd. Representative Patent attorney Fujio Sasashima 1... Starter switch 11... Motor (armature) 12... Field winding 13... Relay 14... Rotation sensor 15... Water temperature sensor 21... Bypass circuit Fig. 6 Fig. 1 Figure 2 Figure 4

Claims (1)

[Claims] A starter motor that generates a magnetic field by passing a current through a field winding to start the engine is provided with a bypass circuit that bypasses the field winding and an opening/closing means for opening and closing the bypass circuit. An engine starting device comprising: an engine state detection means for detecting an engine state; and a control means for controlling opening and closing of the opening and closing means according to the engine state.