WO2016021003A1

WO2016021003A1 - Engine-starting control device, and engine-starting control method

Info

Publication number: WO2016021003A1
Application number: PCT/JP2014/070738
Authority: WO
Inventors: 匡史岩本; 手塚　淳
Original assignee: 日産自動車株式会社
Priority date: 2014-08-06
Filing date: 2014-08-06
Publication date: 2016-02-11

Abstract

This engine-starting control device is provided with: an electrical storage means capable of at least electrical discharge; a starting electric motor which starts an engine as a result of being rotationally driven by electric power supplied from the electrical storage means; a voltage detection means for detecting the voltage of the electrical storage means; a first electric-power supply passage for supplying the electric power from the electrical storage means to the starting electric motor; a second electric-power supply passage which is for supplying the electric power from the electrical storage means to the starting electric motor, and which has a higher resistance value than the first electric-power supply passage; and a selection means which, in cases when the voltage of the electrical storage means is higher than a prescribed threshold voltage when starting the engine, selects the second electric-power supply passage, and which, in cases when the voltage of the electrical storage means is equal to or less than the prescribed threshold voltage when starting the engine, selects the first electric-power supply passage.

Description

Engine start control device and engine start control method

The present invention relates to an engine start control device and an engine start control method.

2. Description of the Related Art Conventionally, a system is known that includes a battery and a capacitor as power storage means, and starts the engine by supplying power from the battery to the starter motor and operating the starter motor when the engine is started (Mazda Technical Report No. 30). (2012), pp. 37-42, “Development of Deceleration Energy Regeneration System“ i-ELOOP ””.

Here, it is conceivable to start the engine by supplying power from the capacitor to the starter motor instead of the battery. However, since the voltage of the capacitor greatly varies depending on the state of charge (SOC), the engine start time differs depending on whether the capacitor voltage is high or low, which gives the driver a sense of incongruity.

It is an object of the present invention to provide a technique for reducing the difference in engine start time that occurs between when the capacitor voltage is high and when the engine is started when power is supplied from the capacitor to the starter motor. .

An engine start control apparatus according to an aspect of the present invention includes at least a dischargeable power storage unit, a starter motor that rotates by electric power supplied from the power storage unit, and starts the engine, and a voltage that detects a voltage of the power storage unit Detection means, a first power supply passage that is a passage for supplying power from the power storage means to the starter motor, and a passage that supplies power from the power storage means to the starter motor and is more resistant than the first power supply passage. A second power supply passage having a high value. The engine start control device further selects the second power supply path when the voltage of the power storage means is higher than a predetermined threshold voltage when starting the engine, and the voltage of the power storage means is set to a predetermined threshold value. When the voltage is equal to or lower than the voltage, selection means for selecting the first power supply path is provided.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a diagram showing a configuration of an engine start system including an engine start control device according to an embodiment. FIG. 2 is a flowchart showing a processing procedure when starting the engine by supplying electric power from the capacitor to the starter motor. FIG. 3 is a diagram for explaining the current flowing through the starter motor in accordance with the voltage of the capacitor when the engine is started using the conventional engine start control device. FIG. 4 is a diagram for explaining the current flowing through the starter motor in accordance with the voltage of the capacitor when the engine is started using the engine start control device according to the embodiment. FIG. 5 is a diagram for explaining the current flowing through the starter motor according to the voltage of the capacitor when the resistance value of the resistor in the ICR relay is reduced. FIG. 6 is a diagram for explaining the current flowing through the starter motor according to the voltage of the capacitor when the resistance value of the resistor in the ICR relay is increased.

FIG. 1 is a diagram showing a configuration of a vehicle engine start system including an engine start control device according to an embodiment. The engine start control device in this embodiment is mounted on a vehicle such as a gasoline vehicle equipped with a gasoline engine, a diesel vehicle equipped with a diesel engine, and a hybrid vehicle equipped with an engine and a motor as a travel drive source.

The battery 1 is a lead acid battery, for example, and supplies power to the starter motor 4 and / or the electric load 9.

The capacitor (power storage means) 2 is, for example, an electric double layer capacitor. The capacitor 2 is characterized in that it is less deteriorated due to charge / discharge than the battery 1 and can be charged / discharged in a short time. The electric power generated by the regenerative operation of the alternator 6 is charged in the capacitor 2 during regenerative braking of the vehicle. However, this regenerative power can be charged to the battery 10 via the DC / DC converter 3. The electric power of the capacitor 2 can be supplied to the electric load 9 and the starter motor 4. Note that the time of regenerative braking of the vehicle includes a time when a brake operation is performed by the driver and a time when the driver decelerates by releasing the accelerator pedal while the vehicle is traveling.

The starter motor (starting motor) 4 is rotationally driven by the supplied electric power, rotates the crankshaft, and starts the engine 10. In FIG. 1, the engine 10 and the alternator 6 are shown at positions apart from each other, but the alternator 4 is actually disposed close to the regenerative operation by the rotational force of the engine 10.

A DC / DC converter 3 is provided between the battery 1 and the capacitor 2. The DC / DC converter 3 adjusts the voltage when power is supplied from the capacitor 2 to the starter motor 4, the electric load 9, and the battery 1. Further, when power is supplied from the battery 1 to the capacitor 2, the voltage is adjusted (current value is limited). Control of the DC / DC converter 3 is performed by a controller 7 which will be described later.

The DC / DC converter 3 can be electrically connected between the battery 1 and the capacitor 2 and electrically disconnects the battery 1 and the capacitor 2 after the ignition switch (not shown) is turned off. This is because when the ignition switch is turned off and the battery 1 and the capacitor 2 are electrically connected, power is continuously supplied from the battery 1 to the capacitor 2, and the self-discharge of the capacitor 2 This is because the power of both the capacitor 2 and the battery 1 is lost.

The changeover switch 5 is controlled by a controller 7 described later, and switches the power supply route to the starter motor 4 between the battery 1 and the capacitor 2 based on a command signal from the controller 7.

The voltage sensor (voltage detection means) 8 detects the voltage of the capacitor 2.

An ICR (Inrush Current Reduction) relay 11 is a relay whose internal resistance changes according to ON / OFF of the relay, and is provided on a line 12 connecting the capacitor 2 and the changeover switch 5. The line 12 is provided in parallel with a line connecting the capacitor 2 and the changeover switch 5 via the DC / DC converter 3. When the ICR relay 11 is on, the line 11b passing through the resistor 11a provided therein is conducted, and when the ICR relay 11 is off, the line 11c without a resistor is conducted. On / off of the ICR relay 11 is controlled by the controller 7.

Controller (selection means) 7 controls the entire vehicle. In particular, the controller 7 performs an engine start process described later.

As described above, the vehicle including the engine start control device according to the embodiment includes the battery 1 and the capacitor 2, and supplies power to the starter motor 4 from either the battery 1 or the capacitor 2. Thus, the engine 10 can be started. The present invention relates to control in the case of starting the engine 10 by supplying electric power from the capacitor 2 to the starter motor 4. This engine start includes not only the initial start based on the engine start operation of the driver, but also the engine restart after the so-called idling stop and the so-called coast stop that automatically stops the engine during inertial running while the vehicle is running. This includes restarting the engine after a while.

FIG. 2 is a flowchart showing a processing procedure when power is supplied from the capacitor 2 to the starter motor 4 to start the engine 10. The process starting from step S1 is performed by the controller 7.

In step S1, it is determined whether or not the voltage of the capacitor 2 detected by the voltage sensor 8 is higher than a predetermined threshold voltage. The predetermined threshold voltage is a determination voltage for switching on / off of the ICR relay 11, and is determined by a method described later. If it is determined that the voltage of the capacitor 2 is higher than the predetermined threshold voltage, the process proceeds to step S2, and if it is determined that the voltage of the capacitor 2 is equal to or lower than the predetermined threshold voltage, the process proceeds to step S3.

In step S2, the ICR relay 11 is turned on.

On the other hand, in step S3, the ICR relay 11 is turned off.

In step S4, a control signal for setting the power supply source of the starter motor 4 to the capacitor 2 is transmitted to the changeover switch 5. The changeover switch 5 connects the starter motor 4 and the capacitor 2 based on this control signal. Thereby, the line 12 connecting the capacitor 2 and the changeover switch 5 is conducted.

In step S5, a starter relay (not shown) is turned on, and power is supplied from the capacitor 2 to the starter motor 4, whereby the starter motor 4 is operated and the engine 10 is started.

First, in order to explain the control effect of the engine start control device in one embodiment, the control result of the conventional engine start control device will be described. In the conventional engine start control device, the ICR relay 11 is not provided on the line 12 connecting the capacitor 2 and the changeover switch 5 in FIG.

FIG. 3 is a diagram for explaining the current flowing through the starter motor 4 according to the voltage of the capacitor 2 when the engine is started using a conventional engine start control device. In FIG. 3, line L1 and line L2 indicate the relationship of the terminal voltage of the capacitor 2 with respect to the current (starter current in the figure) flowing through the starter motor 4 when the engine is started. The line L1 indicates that the voltage of the capacitor 2 is the highest voltage. In this case, the line L2 indicates the case where the voltage of the capacitor 2 is the lowest voltage. A region between the line L1 and the line L2 is a working voltage range of the capacitor 2.

Line L3 shows the relationship between the voltage drop amount obtained by adding the voltage drop of the harness and the voltage drop due to the resistance of the starter motor 4 to the current flowing through the starter motor 4 when the engine is started. The voltage drop of the harness is a voltage drop generated in the harness connecting between the capacitor 2 and the starter motor 4. A current Ia at the intersection of the line L3 and the line L2 is a current that flows to the starter motor 4 when the voltage of the capacitor 2 is the lowest voltage. Further, the current Ib at the intersection of the line L3 and the line L1 is a current that flows to the starter motor 4 when the voltage of the capacitor 2 is the highest voltage.

In the conventional engine start control device, the current flowing through the starter motor 4 at the time of engine start varies greatly depending on the voltage of the capacitor 2. Since the current Ib flowing through the starter motor 4 at the maximum voltage of the capacitor 2 is large, a method of providing a large resistance in the current path from the capacitor 2 to the starter motor 4 is considered so that the life of the starter motor 4 is not deteriorated by this current Ib. It is done. However, when a large resistance is provided, if the voltage of the capacitor 2 is low, a current sufficient for starting the engine may not flow to the starter motor 4, and the startability of the engine 10 is deteriorated.

On the other hand, if a small resistance is provided in the current path from the capacitor 2 to the starter motor 4 so that a sufficient current flows through the starter motor 4 at the lowest voltage of the capacitor 2, the starter motor 4 has a high voltage when the voltage of the capacitor 2 is high. Since the flowing current increases, the life of the starter motor 4 is deteriorated.

FIG. 4 is a diagram for explaining a current flowing through the starter motor 4 according to the voltage of the capacitor 2 when the engine is started using the engine start control device according to the embodiment. The lines L1 to L3 are the same as the lines L1 to L3 in FIG. However, in the engine start control device according to the embodiment, the ICR relay 11 is provided on the line 12 connecting the capacitor 2 and the changeover switch 5 in FIG. 1, and the line L3 in FIG. The line when off.

As described above, the line L3 indicates a line when the ICR relay 11 is off, while the line L4 indicates a line when the ICR relay 11 is on. That is, the line L4 in FIG. 4 shows the voltage drop of the harness, the voltage drop due to the resistance of the starter motor 4 with respect to the current flowing through the starter motor 4 when the engine is started, and the voltage of the ICR relay 11 when the ICR relay 11 is on. The relationship with the voltage drop allowance added to the drop is shown. When the ICR relay 11 is turned on, the current from the capacitor 2 flows through the resistor 11 a provided inside the ICR relay 11. The voltage drop of the ICR relay 11 is a voltage drop caused by a current flowing through the resistor 11a.

4 also shows a line L5 indicating a predetermined threshold voltage for switching the ICR relay 11 on / off.

In this embodiment, when the voltage of the capacitor 2 is equal to or lower than a predetermined threshold voltage, the ICR relay 11 is turned off. The voltage drop margin for the current flowing through the starter motor 4 when the engine is started when the ICR relay 11 is off is a line L3. Therefore, the current Ia at the intersection of the line L3 and the line L2 becomes a current that flows to the starter motor 4 when the voltage of the capacitor 2 is the lowest voltage. Further, the current Ic at the intersection of the line L3 and the line L5 becomes a current that flows through the starter motor 4 when the voltage of the capacitor 2 is a predetermined threshold voltage.

When the voltage of the capacitor 2 becomes higher than a predetermined threshold voltage, the ICR relay 11 is turned on. A voltage drop margin with respect to a current flowing through the starter motor 4 when the engine is started when the ICR relay 11 is on is a line L4. Therefore, the current at the intersection of the line L4 and the line L5 becomes the current that flows to the starter motor 4 when the voltage of the capacitor 2 is the predetermined threshold voltage. Further, the current Ic at the intersection of the line L4 and the line L3 is a current that flows to the starter motor 4 when the voltage of the capacitor is the highest voltage.

As apparent from FIGS. 3 and 4, in the conventional engine start control device, when the voltage of the capacitor 2 is between the minimum voltage and the maximum voltage, the minimum value of the current flowing through the starter motor 4 when the engine is started is Ia. The highest value was Ib. However, according to the engine start control device of the present embodiment, the minimum value of the current flowing through the starter motor 4 when the engine is started is Ia and the maximum value is Ic (Ic <Ib). That is, the width (current difference) of the current flowing through the starter motor 4 at the time of starting the engine with respect to the fluctuation range of the voltage of the capacitor 2 is small. As a result, even when the voltage of the capacitor 2 fluctuates greatly, the time required to start the engine does not change significantly, so that the driver does not feel uncomfortable when starting the engine.

Here, in the present embodiment, the maximum value (Ic) of the current flowing through the starter motor 4 when the ICR relay 11 is turned on is the same as the maximum value (Ic) of the current flowing through the starter motor 4 when the ICR relay 11 is turned off. The resistance value of the resistor 11a in the ICR relay 11 and a predetermined threshold voltage are set. The reason for this will be described below.

FIG. 5 is a diagram for explaining the current flowing through the starter motor 4 according to the voltage of the capacitor 2 when the resistance value of the resistor 11a in the ICR relay 11 is reduced. The case where the resistance value of the resistor 11a is reduced is a case where the resistance value is reduced with reference to the resistance value for realizing the state shown in FIG.

In FIG. 5, a line L3a is a line when the ICR relay 11 is OFF, and the voltage drop of the harness and the voltage drop due to the resistance of the starter motor 4 are added to the current flowing through the starter motor 4 when the engine is started. The relationship with the voltage drop is shown. A line L4a is a line when the ICR relay 11 is on. The voltage drop of the harness, the voltage drop due to the resistance of the starter motor 4 with respect to the current flowing through the starter motor 4 when the engine is started, and the ICR relay 11 The relationship with the voltage drop allowance which added the voltage drop part of the ICR relay 11 at the time of ON is shown. Here, the predetermined threshold voltage (line L5a) is set so that the current flowing through the starter motor 4 becomes Ia when the ICR relay 11 is switched from OFF to ON.

When the voltage of the capacitor 2 becomes higher than a predetermined threshold voltage, the ICR relay 11 is turned on. In this case, the current Ia at the intersection of the line L4a and the line L5a is a current that flows to the starter motor 4 when the voltage of the capacitor 2 is a predetermined threshold voltage. Further, the current Id at the intersection of the line L4a and the line L1 is a current that flows to the starter motor 4 when the voltage of the capacitor is the highest voltage. In this case, as apparent from FIG. 5, the starter motor 4 has a larger current value Ic when the ICR relay 11 is on and off than when the Ic is the same (see FIG. 4). The maximum value of the flowing current increases (Id> Ic).

FIG. 6 is a diagram for explaining the current flowing through the starter motor 4 according to the voltage of the capacitor 2 when the resistance value of the resistor 11a in the ICR relay 11 is increased. The case where the resistance value of the resistor 11a is increased is a case where the resistance value is increased based on the resistance value for realizing the state shown in FIG.

In FIG. 6, a line L3b is a line when the ICR relay 11 is OFF, and the voltage drop of the harness and the voltage drop due to the resistance of the starter motor 4 are added to the current flowing through the starter motor 4 when the engine is started. The relationship with the voltage drop is shown. A line L4b is a line when the ICR relay 11 is on. The voltage drop of the harness, the voltage drop due to the resistance of the starter motor 4 with respect to the current flowing through the starter motor 4 when the engine is started, and the ICR relay 11 The relationship with the voltage drop allowance which added the voltage drop part of the ICR relay 11 at the time of ON is shown. Here, a predetermined threshold voltage (line L5b) is set so that the current flowing through the starter motor 4 becomes Ia when the ICR relay 11 is switched from OFF to ON.

When the voltage of the capacitor 2 is equal to or lower than a predetermined threshold voltage, the ICR relay 11 is off. Therefore, the current Ie at the intersection of the line L3b and the line L5b becomes a current that flows to the starter motor 4 when the voltage of the capacitor 2 is a predetermined threshold voltage. Therefore, when the ICR relay 11 is turned on and off, the maximum value of the current flowing through the starter motor 4 is larger than when the maximum value of the current flowing through the starter motor 4 is the same as Ic (see FIG. 4) ( Ie> Ic).

As described above, when the maximum value of the current flowing through the starter motor 4 is the same when the ICR relay 11 is turned on and off, the current flowing through the starter motor 4 can be most suppressed.

As described above, according to the engine start control device in the embodiment, when the voltage of the capacitor 2 is equal to or lower than the predetermined threshold voltage when the engine 10 is started, power is supplied from the capacitor 2 to the starter motor 4. When the first power supply passage (line 12, line 11c) which is a passage is selected and the voltage of the capacitor 2 is higher than a predetermined threshold voltage, the first power supply passage having a resistance value higher than that of the first power supply passage. Two power supply paths (line 12, line 11b) are selected. As a result, when the voltage of the capacitor 2 is high, power is supplied from the capacitor 2 to the starter motor 4 via the second power supply path having a high resistance value, thereby preventing a large current from flowing through the starter motor 4. It is possible to suppress the deterioration of the life of the starter motor 4. When the voltage of the capacitor 2 is equal to or lower than a predetermined threshold voltage, power is supplied from the capacitor 2 to the starter motor 4 through the first power supply path having a low resistance value, so the engine 10 is started. Therefore, a sufficient current can be supplied to the starter motor 4, and good engine startability can be ensured.

Further, the maximum current that flows to the starter motor 4 when the first power supply passage is selected and the maximum current that flows to the starter motor 4 when the second power supply passage is selected are substantially the same. The resistance value and threshold voltage of the second power supply passage are set. Thereby, the electric current which flows into the starter motor 4 can be suppressed most.

Further, an ICR relay 11 having a resistor 11 a provided therein is provided between the capacitor 2 and the starter motor 4, and the first power supply path is a resistor 11 a provided inside the ICR relay 11. The second power supply path is a power supply path that passes through a resistor 11 a provided inside the ICR relay 11. Thereby, the first power supply path and the second power supply path can be easily switched by turning on / off the ICR relay 11.

The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent. For example, in the above-described embodiment, power is supplied from the capacitor 2 to the starter motor 4 to start the engine. However, the power supply source to the starter motor is not limited to the capacitor, for example, lithium ion A battery such as a battery may be used. It should be noted that the present invention is particularly effective when applied to a system that supplies power to a starting motor for starting an engine from power storage means whose voltage varies greatly depending on the state of charge.

Alternatively, the engine 1 may be started by driving the alternator 4 as a starting motor instead of the starter motor 4.

Claims

At least a dischargeable power storage means;
A starting electric motor that is rotated by electric power supplied from the power storage means and starts the engine;
Voltage detection means for detecting the voltage of the power storage means;
A first power supply path that is a path for supplying power from the power storage means to the starting motor;
A passage for supplying power from the power storage means to the starter motor, a second power supply passage having a resistance value higher than that of the first power supply passage;
When the engine is started, if the voltage of the power storage means is higher than a predetermined threshold voltage, the second power supply passage is selected, and the voltage of the power storage means is less than or equal to the predetermined threshold voltage. A selection means for selecting the first power supply path;
An engine start control device comprising:
The engine start control device according to claim 1,
The maximum current flowing through the starting motor when the first power supply passage is selected and the maximum current flowing through the starting motor when the second power supply passage is selected are substantially the same. In addition, the resistance value of the second power supply passage and the threshold voltage are set.
Engine start control device.
The engine start control device according to claim 1 or 2,
Between the power storage means and the starting motor, there is provided an ICR relay provided with a resistance inside,
The first power supply path is a power supply path that does not pass through a resistor provided in the ICR relay, and the second power supply path is a power supply path that passes through a resistor provided in the ICR relay. Is,
Engine start control device.
In the engine start control method for starting the engine by supplying electric power from the power storage means to the starter motor and rotating the starter motor,
Detecting the voltage of the power storage means at the start of the engine;
When the detected voltage of the power storage means is equal to or lower than a predetermined threshold voltage, power is supplied from the power storage means to the starter motor via the first power supply path, and the detected power storage means Is higher than the predetermined threshold voltage, electric power is supplied from the power storage means to the starter motor via the second power supply path having a resistance value higher than that of the first power supply path. Supply,
Engine start control method.