JP6544164B2 - Engine start method, engine start device - Google Patents

Description

  The present invention relates to an engine starting method and an engine starting device.

  Generally, power is supplied from a lead storage battery to start the engine. However, the lead storage battery has a characteristic that the durability is low against frequent charging and discharging. Therefore, in the prior art described in Patent Document 1, a high performance storage battery is connected in parallel with a lead storage battery only when the engine is automatically stopped and restarted by an idling stop function, and these lead storage battery and high performance storage battery Power supply is proposed.

Patent No. 5541134

In the above-mentioned prior art, when the driver first starts the engine, power is supplied only by the lead-acid battery, so if, for example, the state of charge of the lead-acid battery is lowered, the engine may not start. is there.
An object of the present invention is to assist the start of the engine.

  An engine start method according to an aspect of the present invention diagnoses a state of a main storage battery. Then, when it is determined that the engine can not be started by the power supplied from the main storage battery as a result of the diagnosis, when starting the engine next time, the power from the auxiliary storage battery having higher durability against repeated charging and discharging than the main storage battery is used. Supply and start the engine.

  According to the present invention, when it is determined that the engine can not be started by the power supplied from the main storage battery, the power is supplied from the secondary storage battery to start the engine, so that the start of the engine can be assisted.

It is a block diagram of an idling stop system. It is a block diagram of a power supply circuit. It is a flowchart which shows start switching processing. It is a map used for the diagnosis of the main battery. It is a flow chart which shows preliminary start processing. It is a block diagram of the power supply circuit in 2nd Embodiment. It is a flow chart which shows preliminary start processing of a 2nd embodiment.

  Hereinafter, embodiments of the present invention will be described based on the drawings. Each drawing is schematic and may be different from the actual one. In addition, the following embodiments illustrate apparatuses and methods for embodying the technical idea of the present invention, and the configuration is not specified to the following. That is, the technical idea of the present invention can be variously modified within the technical scope described in the claims.

First Embodiment
"Constitution"
First, an outline of the idling stop system will be described.
The idling stop (IS) is a function of automatically stopping the engine when the vehicle is stopped at an intersection, traffic jam or the like, and restarting it at the time of start, and is also called no idling or idle reduction.
FIG. 1 is a block diagram of the idling stop system.
In the idling stop system, the controller (ECU: Electronic Control Unit) 11 executes idling stop in accordance with detection values from various sensors. The various sensors include, for example, a wheel speed sensor 12, a master back pressure sensor 13, an accelerator sensor 14, an acceleration sensor 15, an engine rotation sensor 16, a shift sensor 17, an idling stop OFF switch 18, and the like.

The wheel speed sensor 12 detects the wheel speeds VwFL to VwRR of the respective wheels. The wheel speed sensor 12 detects, for example, magnetic lines of force of the sensor rotor by a detection circuit, converts a change in magnetic field accompanying the rotation of the sensor rotor into a current signal, and outputs the current signal to the controller 11. The controller 11 determines the wheel speeds VwFL to VwRR from the input current signal.
The master back pressure sensor 13 detects the pressure in the master back (brake booster) as the brake pedal depression force Pb. The master back pressure sensor 13 receives the pressure in the master back at the diaphragm portion, detects distortion generated in the piezoresistive element through the diaphragm portion as a change in electric resistance, and converts it into a voltage signal proportional to the pressure. It outputs to the controller 11. The controller 11 determines the pressure in the master back, that is, the brake pedal depression force Pb from the input voltage signal.

  The accelerator sensor 14 detects a pedal opening degree PPO (operation position) corresponding to the depression amount of the accelerator pedal. The accelerator sensor 14 is, for example, a potentiometer, converts the pedal opening degree PPO of the accelerator pedal into a voltage signal, and outputs the voltage signal to the controller 11. The controller 11 determines the pedal opening degree PPO of the accelerator pedal from the input voltage signal. When the accelerator pedal is in the non-operation position, the pedal opening degree PPO is 0%, and when the accelerator pedal is in the maximum operation position (stroke end), the pedal opening degree PPO is 100%.

The acceleration sensor 15 detects acceleration / deceleration in the longitudinal direction of the vehicle. The acceleration sensor 15 detects, for example, the positional displacement of the movable electrode relative to the fixed electrode as a change in capacitance, converts it into a voltage signal proportional to the degree of acceleration and deceleration, and outputs the voltage signal to the controller 11. The controller 11 determines the acceleration / deceleration from the input voltage signal. The controller 11 processes acceleration as a positive value and processes deceleration as a negative value.
The engine rotation sensor 16 detects an engine rotation speed Ne. The engine rotation sensor 16 detects magnetic lines of force of the sensor rotor, for example, by a detection circuit, converts a change in magnetic field accompanying the rotation of the sensor rotor into a current signal, and outputs the current signal to the controller 11. The controller 11 determines the engine speed Ne from the input current signal.

The shift sensor 17 detects the shift position of the transmission. The shift sensor 17 includes, for example, a plurality of Hall elements, and outputs respective ON / OFF signals to the controller 11. The controller 11 determines the shift position from the combination of the input ON / OFF signal.
The idling stop OFF switch (IS-OFF switch) 18 detects a cancellation operation of the idling stop system. The idling stop OFF switch 18 is provided in the vicinity of the dashboard so as to be operable by the driver, and outputs, for example, a voltage signal corresponding to the cancel operation to the controller 11 via the detection circuit of the normally closed contact. The controller 11 determines from the input voltage signal whether to cancel the idling stop function.

The controller 11 performs fuel injection control via a fuel injector, and performs ignition timing control via an ignition coil to control stop and restart of the engine (ENG) 21. Also, at the time of restart, cranking by the starter motor (SM) 22 is controlled.
The starter motor 22 is, for example, a series wound commutator motor, and cranks the engine 21 by transmitting a torque by meshing a pinyon gear of an output shaft with a ring gear of the engine 21. The starter motor 22 includes a solenoid that slides the pinonion shaft in the axial direction to move back and forth between a protruding position that meshes with the ring gear of the engine 21 and a retracted position that does not mesh with it, and a gear mechanism that reduces the rotation of the rotation shaft. Prepare.
The power of the engine 21 is transmitted to the alternator (ALT) 24 via a serpentine V-belt 23. The alternator 24 generates electric power by the power transmitted through the V-belt 23, and the generated electric power is supplied to a power supply circuit described later. The alternator 24 incorporates a regulator, and the generated voltage is controlled via the regulator.

Next, an operation outline of the idling stop will be described.
In the idling stop system, for example, when all the following permission conditions are satisfied, the system enters a standby state in which idling stop is permitted.
· IS-OFF switch 88 is not in operation (idling stop function is ON)
・ The charge state (SOC) of the battery is, for example, 70% or more. ・ The shift position is not in the R range.

From the above standby state, the engine 21 is stopped when all the following operating conditions are satisfied and, for example, one second has elapsed.
・ The vehicle speed V is 0 km / h
・ The accelerator pedal opening PPO is 0%
The brake pedal depression force Pb is, for example, 0.8 MPa or more. The road surface gradient is, for example, 14% or less. The engine rotational speed Ne is, for example, less than 1,200 rpm Here, the average value of the wheel speeds VwFL to VwRR is used as the vehicle speed V. Also, the road surface slope is calculated according to the acceleration / deceleration. The road surface gradient is calculated as (vertical distance / horizontal distance) × 100, and for example, low-pass filter processing of 1 Hz is performed.

The engine 21 is restarted when any of the following restart conditions are satisfied from the above-described stop state.
・ Start steering operation from idling stop ・ Vehicle speed V is 2km / h or more ・ Accelerator pedal opening PPO is 5% or more ・ Shift operation from P range to R range or D range ・ N range to R range or D Shift operation to range • Shift operation from D range to R range The above is an outline of the operation of the idling stop.

  The controller 11 performs voltage variable control to control the generated voltage of the alternator 24 in a range of 11.4 to 15.6 V, for example. That is, the target power generation voltage is calculated according to the traveling state of the vehicle and the charge state of the battery, and the power generation voltage of the alternator 24 is controlled via the regulator according to the calculated target power generation voltage. For example, when the vehicle accelerates, the load on the engine 21 can be reduced and the fuel consumption can be reduced by lowering the generated voltage of the alternator 24 than usual. When the voltage variable control is disabled, the alternator 24 performs normal power generation according to the characteristics of the regulator.

Next, the configuration of the power supply circuit will be described.
FIG. 2 is a block diagram of a power supply circuit.
The power supply circuit 31 is a circuit that supplies power to the starter motor 22 and the other electrical loads 25, and includes a main battery 32, a sub-battery 33, and a relay 34. The power supply circuit 31 also supplies power to the controller 11.
For example, a lead storage battery is used for the main battery 32, lead dioxide is used for the positive electrode, cancellous lead is used for the negative electrode, and dilute sulfuric acid is used for the electrolyte. The main battery 32 is charged by the power generated by the alternator 24, and the open circuit voltage in a fully charged state is, for example, 12.7V.

  The sub battery 33 is provided in order to prevent the power supply voltage of the vehicle from being instantaneously reduced by the large current flowing through the starter motor 22 when the engine 21 is restarted from the idling stop. For example, a lithium ion battery, which is a type of non-aqueous electrolyte secondary battery, is used for the sub-battery 33. A lithium metal oxide is used for the positive electrode, and a carbon material such as graphite is used for the negative electrode. The sub-battery 33 is charged by the electric power generated by the alternator 24, and the open circuit voltage in the fully charged state is 13.1 V, for example.

  Lithium ion batteries are characterized by having high energy density and charge / discharge energy efficiency as compared with lead storage batteries. In addition, since the lithium ion battery does not involve the dissolution and deposition reaction of the electrode material during charge and discharge, a long life can be expected. On the other hand, lead-acid batteries are less expensive than lithium-ion batteries if they have the same capacity, but the electrodes are degraded by discharging. Therefore, the lithium ion battery is superior to the lead storage battery in durability against repeated charging and discharging.

  The relay 34 is a switch that switches whether the sub-battery 33 is connected to the power supply circuit 31 or disconnected from the power supply circuit 31, and is controlled by the controller 11. The relay 34 is a normally open a contact, which disconnects the sub battery 33 from the power supply circuit 31 when the contact is open, and connects the sub battery 33 to the power supply circuit 31 when the contact is closed. Specifically, while the engine 21 is in operation, the sub battery 33 is connected to the power supply circuit 31, and the power supplied from the alternator 24 is charged to the sub battery 33. Further, when restarting the engine 21 from the idling stop, the sub battery 33 is connected to the power supply circuit 31 to supply power to the starter motor 22. Furthermore, when performing the preliminary start process, the sub-battery 33 is connected to the power supply circuit 31 to supply power to the starter motor 22.

Next, the start switching process executed by the controller 11 will be described.
FIG. 3 is a flowchart showing the start switching process.
In step S101, it is determined whether the engine 21 is in the operation stop state. When the engine 21 is in the operation stop state, the process proceeds to step S102 because the start process is not completed. On the other hand, when the engine 21 is in the operating state, since the start-up process is completed, the process proceeds to step S106.

In step S102, it is determined whether there is a driver's start operation such as a driver's key operation or button operation. When the driver's start operation is performed, the process proceeds to step S103 to perform the start process. On the other hand, when the driver does not perform the start operation, the start process is unnecessary, so the process returns to the predetermined main program.
In step S103, it is determined whether the switching flag is reset to fs = 0. When the switching flag is reset to fs = 0, the process proceeds to step S104 to perform normal start. On the other hand, when the switching flag is set to fs = 1, the process proceeds to step S105 to perform the prestart.

In step S104, the normal start process is performed, and then the process proceeds to step S106. That is, electric power is supplied from the main battery 32 to crank the engine 21.
In step S105, the process proceeds to step S106 after the preliminary start process described later is performed. That is, the electric power is supplied from the sub battery 33 to perform the cranking of the engine 21.
In step S106, the state of the main battery 32 is diagnosed. Specifically, the operation of the engine 21 is stopped, and then it is diagnosed whether or not the engine 21 can be started only by the power supplied from the main battery 32, that is, whether or not the normal start can be performed.

Whether or not the normal start can be performed is diagnosed according to, for example, the state of charge (SOC) or the state of health (SOH) of the main battery 32. The state of charge is the ratio of the remaining charge to the charge capacity. The degraded state is the ratio of the current full charge capacity to the full charge capacity at the time of shipment.
Alternatively, depending on the minimum voltage of main battery 32 when power is supplied from main battery 32 to start engine 21 and the charge / discharge amount of main battery 32 after engine 21 is started, main battery 32 To diagnose the condition of The minimum voltage changes depending on the state of the main battery 32, and the lower the state of the main battery 32, the lower the minimum voltage tends to be. The charge and discharge amount is a value obtained by integrating the charge amount and the discharge amount after the engine 21 is started.

FIG. 4 is a map used for diagnosis of the main battery.
(A) in the figure is a map for diagnosing the state of the main battery 32 according to the SOC _Main . Here, it is determined that normal start can be performed when SOC _Main is equal to or greater than predetermined threshold value th1, and normal start can not be performed when SOC _Main is less than threshold value th1, that is, it is determined that preliminary start is necessary. The threshold th1 is, for example, 50%. Here, whether or not the normal start can be performed is determined according to the charging state of the main battery 32, but the present invention is not limited to this. For example, the determination may be made based on the deterioration state of the main battery 32, or may be made based on both the charge state and the deterioration state.

  (B) in the figure is a map for diagnosing the state of the main battery 32 according to the minimum voltage and the charge / discharge amount. Here, the horizontal axis is the minimum voltage, the vertical axis is the charge / discharge amount, and the characteristic line L1 is set such that the charge / discharge amount decreases as the minimum voltage increases. Then, when the lowest voltage is equal to or higher than the characteristic line L1, it is determined that the normal start can be performed. When the lowest voltage is less than the characteristic line L1, the normal start can not be performed. Similarly, it is determined that the normal start can be performed when the charge / discharge amount is equal to or greater than the characteristic line L1, and the normal start can not be performed when the charge / discharge amount is less than the characteristic line L1, that is, it is determined that the preliminary start is necessary. .

In the following step S107, as a result of diagnosis, it is determined whether or not normal start can be performed. When the normal start can be performed, the process proceeds to step S108. On the other hand, when the normal start can not be performed, that is, when the preliminary start is required, the process proceeds to step S109.
In step S108, the switching flag is reset to fs = 0, and then the process returns to the predetermined main program.
In step S109, the switching flag is set to fs = 1 and then the process returns to the predetermined main program.
The above is the start switching process.

Next, the preliminary start-up process executed in step S105 will be described.
FIG. 5 is a flowchart showing the preliminary start process.
In step S111, it is determined whether the SOC _{Sub of the} sub battery 33 is equal to or greater than a predetermined threshold th2. The threshold th2 is 70%, for example. Here, when the SOC _Sub of the sub battery 33 is greater than or equal to the threshold th2, it is determined that the preliminary start using the sub battery 33 can be tried, and the process proceeds to step S112. On the other hand, when the SOC _Sub of the sub battery 33 is smaller than the threshold value th2, it is determined that the preliminary start using the sub battery 33 can not be tried, and the process returns to the predetermined main program. Here, although it is determined whether or not the preliminary start can be tried according to the charge state of the sub battery 33, the present invention is not limited to this. For example, the determination may be made based on the deterioration state of the sub battery 33 or may be made based on both the charge state and the deterioration state.

  In step S112, it is determined whether the engine hood is closed. Whether the engine hood is closed or open is determined according to, for example, a detection signal of the bonnet switch. Here, when the engine hood is closed, it is determined that the user does not intend a jump start by the external power supply, and the process proceeds to step S113. On the other hand, when the engine hood is open, it is determined that the user may intend to make a jump start by the external power supply, and the process returns to the predetermined main program.

  In step S113, the driver is instructed to connect the sub-battery 33 to the power supply circuit 31 as a preliminary start. That is, for example, on the display, guidance is given on the attempt of the preliminary start and the predetermined operation required for that. The predetermined operation may be to operate a dedicated switch, but it is desirable to use an existing switch. For example, the idling stop OFF switch 18 may be depressed, or the idling stop OFF switch 18 may be depressed while depressing the brake pedal. The driver is guided (prompted) to perform such a predetermined operation.

In the subsequent step S114, it is determined whether or not the driver has performed an operation for connecting the sub-battery 33 to the power supply circuit 31. When the driver performs a predetermined operation, it is determined that the connection of the sub-battery 33 to the power supply circuit 31 is permitted, and the process proceeds to step S115. On the other hand, when the driver does not perform the predetermined operation, it is determined that the connection of the sub battery 33 to the power supply circuit 31 is not permitted, and the process returns to the predetermined main program.
In step S115, the sub battery 33 is connected to the power supply circuit 31 by closing the relay 34.

In the subsequent step S116, the engine start is cranked by the starter motor 22 to try a preliminary start using the sub-battery 33. Here, the number of times of cranking is limited, for example, a few times.
In the following step S117, it is determined whether or not the engine 21 has been successfully started by the preliminary start process. When the start of the engine 21 is successful, the process proceeds to step S118. On the other hand, when the start of the engine 21 fails, the prestart is abandoned and the process proceeds to step S121.

In step S118, for example, the display is displayed on the display to guide the driver that the engine 21 has been successfully started by the preliminary start using the sub-battery 33 and that the maintenance inspection of the main battery 32 should be performed early. ). In addition, you may light a warning lamp instead of displaying on a display.
In the subsequent step S119, the idling stop control is invalidated. Here, although idling stop control is invalidated, it is not limited to this, and the engine stop function which makes engine 21 stop automatically according to a vehicle state is invalidated.
In the subsequent step S120, after the variable voltage control is invalidated, the process returns to the predetermined main program.
In step S121, by opening the relay 34, the sub-battery 33 is disconnected from the power supply circuit 31, and the process returns to the predetermined main program.
The above is the preliminary start process.

<< Operation >>
Next, the operation of the first embodiment will be described.
Electric power is supplied from the lead storage battery serving as the main battery 32 for starting the engine 21. However, the lead storage battery has a characteristic that the durability is low against frequent charging and discharging. Therefore, when restarting the engine 21 after automatic stop (temporary stop) by idling stop, a lithium ion battery to be the sub battery 33 is connected in parallel with the lead storage battery, and the main battery 32 and the sub battery 33 Supply power.

  As a result, even if automatic stop and restart of the engine 21 are repeatedly performed by idling stop, frequent charging and discharging of the main battery 32 can be suppressed, and early deterioration can be suppressed. In addition, when the engine 21 is restarted from the idling stop, it is possible to prevent the power supply voltage of the vehicle from being instantaneously lowered by the large current flowing through the starter motor 22.

  When the engine 21 is in operation, the sub-battery 33 is connected to the power supply circuit 31. Thus, both the main battery 32 and the sub-battery 33 are charged by the power generated by the alternator 24. Further, after stopping the operation of the engine 21 in response to the driver's stop operation such as the driver's key operation or button operation from the state where the engine 21 is operating, the sub-battery 33 is disconnected from the power supply circuit 31 . This can prevent the discharge of the sub-battery 33 due to dark current.

Then, when the engine 21 is started according to the driver's start operation such as the driver's key operation or button operation from the state where the operation of the engine 21 is stopped, the electric power is generated only by the main battery 32 of the lead storage battery. It will supply.
However, if the state of charge of the main battery 32 is lowered, there is a possibility that the engine 21 can not be started. Therefore, in a state where the engine 21 is operated, the state of the main battery 32 is diagnosed (step S106). That is, the operation of the engine 21 is stopped, and then it is diagnosed whether or not the engine 21 can be started only by the power supplied from the main battery 32, that is, whether or not the normal start can be performed.

Then, when the normal start can be performed (the determination in step S107 is “Yes”), the switching flag is reset to fs = 0 (step S108). Thereby, when starting the engine 21 next time, electric power is supplied from the main battery 32 to start the engine 21 as usual.
On the other hand, when the normal start can not be performed (the determination in step S107 is “No”), the switching flag is set to fs = 1 (step S109). As a result, when the engine 21 is started next time, electric power is supplied from the sub-battery 33 to start the engine 21 as a preliminary start process.

Specifically, after the sub-battery 33 is connected to the power supply circuit 31 via the relay 34 (step S115), the engine 21 is started (step S116). As described above, when it is determined that the electric power supplied from the main battery 32 can not start the engine 21, the electric power is supplied from the sub-battery 33 to start the engine 21. Therefore, the start of the engine 21 can be assisted. . Further, by connecting or disconnecting the sub-battery 33 via the relay 34, switching can be easily and reliably performed.
In the preliminary start process, when the SOC _{Sub of the} sub battery 33 is equal to or greater than the threshold th 2 (the determination in step 111 S is “Yes”), the sub battery 33 is connected to the power supply circuit 31. That is, since the preliminary start is attempted only when the sub battery 33 is in a charging state where the engine 21 can be started, the reliability of the preliminary start is improved.

  Further, when the engine hood is closed (the determination in step S112 is “Yes”), the sub battery 33 is connected to the power supply circuit 31. This is because when the engine hood is open, the user may intend to jump start by the external power supply. If a jump start is performed via the booster cable in a state where the sub battery 33 is connected, an excessive current flows in the sub battery 33. Therefore, by connecting the sub-battery 33 only when the engine hood is closed, it is possible to protect the sub-battery 33 from the large current caused by the jump start.

  Also, the driver is instructed to connect the sub-battery 33 to the power supply circuit 31 (step S113), and when the driver performs an operation along the guidance (the determination in step S114 is "Yes"), The sub battery 33 is connected to the power supply circuit 31. Thus, by confirming with the driver whether or not the sub-battery 33 is to be connected to the power supply circuit 31, it is possible to perform the preliminary start in accordance with the driver's intention. If such confirmation is omitted and the sub-battery 33 is automatically connected to the power supply circuit 31 to perform preliminary start and start is successful, the driver hardly notices that the charging state of the main battery 32 is abnormal. Become. Therefore, the driver can be made aware that an abnormality has occurred in the state of charge of the main battery 32 by following the procedure of driver's confirmation.

  In this operation, the existing switch is used. For example, the idling stop OFF switch 18 may be depressed, or the idling stop OFF switch 18 may be depressed while depressing the brake pedal. As described above, since the intention of the driver is confirmed by utilizing the existing switch, the provision of a dedicated switch can be omitted, and the increase in the number of parts can be suppressed. In the first place, it is not desirable to provide a dedicated switch, since this pre-startup process is not a frequent event and is a unique case. Also, using a completely unrelated switch can lead to driver confusion. However, since the idling stop OFF switch 18 is originally a switch related to the start of the engine 21, it is possible to suppress confusion by using this switch.

A limit is imposed on the cranking of the engine 21 by the prestart. For example, up to a couple of times. As described above, since the number of times is limited, it is possible to prevent the engine 21 from continuing to fail to start many times.
On the other hand, when the start of the engine 21 is successful due to the preliminary start (the determination in step S117 is "Yes"), that is notified to the driver (step S118). At this time, the driver is recommended to carry out maintenance and inspection of the main battery 32 at an early stage. That is, the fact that the engine 21 can not be started only by the main battery 32 is considered to be that the main battery 32 has an abnormality. It is desirable to prompt maintenance of the main battery 32 because the pre-start is a quick fix and is like a first aid measure.

After the engine 21 is successfully started by the preliminary start, the idling stop control is invalidated (step S119). That is, in a situation where the state of charge of the main battery 32 is lowered, the control for automatically stopping the engine 21 is prohibited. Thereby, the main battery 32 can be charged with priority.
In addition, after the start of the engine 21 is successfully completed by the preliminary start, the voltage variable control of the alternator 24 is invalidated (step S120). That is, in a situation where the state of charge of the main battery 32 is lowered, the control for suppressing the generated voltage of the alternator 24 is prohibited. Thereby, the main battery 32 can be charged with priority.
If the start of the engine 21 fails even in the preliminary start (the determination in step S117 is "No"), the sub-battery 33 is disconnected from the power supply circuit 31 via the relay 34. Thereby, it is possible to prepare for jump start from the external power source by the user.

<< Modification >>
In the first embodiment, the idling stop control and the voltage variable control of the alternator 24 are invalidated when the start of the engine 21 succeeds as the preliminary start using the sub-battery 33. May be inhibited or restricted. For example, the operation of an electrical load, such as an air conditioner or a heater, which does not affect the traveling performance of the vehicle may be prohibited or limited. As a result, it is possible to suppress battery drain of the main battery 32.

<< Correspondence relationship >>
Main battery 32 corresponds to the "main storage battery". Sub battery 33 corresponds to the "secondary battery". Relay 34 corresponds to the "switch for auxiliary storage battery". The alternator 24 corresponds to the "generator". The idling stop control corresponds to the "engine stop function". The voltage variable control of the alternator 24 corresponds to the “voltage variable function”. The process of step S106 corresponds to the "diagnosis unit". The process of step S105 (steps S111 to S121) corresponds to the "preliminary start unit".

"effect"
Next, the effect of the main part in the first embodiment will be described.
(1) In the engine starting method according to the first embodiment, the state of the main battery 32 is diagnosed. As a result of the diagnosis, when it is determined that the electric power supplied from the main battery 32 can not start the engine 21, the sub-battery 33 is more durable against repeated charging and discharging than the main battery 32 when the engine 21 is started next time. To supply power to start the engine 21.
As described above, when it is determined that the electric power supplied from the main battery 32 can not start the engine 21, the electric power is supplied from the sub-battery 33 to start the engine 21, thereby assisting the start of the engine 21. it can.

(2) In the engine starting method according to the first embodiment, the minimum voltage of the main battery 32 when power is supplied from the main battery 32 to start the engine 21 and the main battery after starting the engine 21 The state of the main battery 32 is diagnosed according to the charge / discharge amount of 32.
As described above, since the diagnosis is performed according to the minimum voltage and the charge / discharge amount, the state of the main battery 32 can be easily and accurately diagnosed.

(3) In the engine starting method according to the first embodiment, power is supplied from the sub battery 33 when the sub battery 33 is in a predetermined charging state.
Thus, by considering the charge state of the sub-battery 33, the reliability of the start using the sub-battery 33 is improved.
(4) In the engine starting method according to the first embodiment, the electric power is supplied from the sub battery 33 to start the engine 21. When the engine 21 is successfully started, the driver is notified of that.
Thus, by notifying the driver of the success by the start using the sub-battery 33, maintenance and inspection of the main battery 32 can be made conscious.

(5) In the engine starting method according to the first embodiment, the electric power is supplied from the sub-battery 33 to start the engine 21. When the engine 21 is successfully started, the engine stop function is invalidated.
Thus, the main battery 32 can be preferentially charged by disabling the idling stop function.
(6) In the engine starting method according to the first embodiment, power is supplied from the sub-battery 33 to start the engine 21. When the engine 21 is successfully started, the voltage variable function is invalidated.
Thus, the main battery 32 can be preferentially charged by disabling the voltage variable function.

(7) In the engine starting method according to the first embodiment, when the electric power is supplied from the sub-battery 33 to start the engine 21, the number of times is limited.
As described above, by setting the number of times of restriction, it is possible to suppress that the start using the sub-battery 33 continues to fail many times.
(8) In the engine starting method according to the first embodiment, when the engine hood is open, the power supply from the sub-battery 33 is prohibited.
By thus prohibiting the power supply from the sub-battery 33, it is possible to prevent interference with the jump start and protect the sub-battery 33.

(9) In the engine starting method according to the first embodiment, the driver is asked whether the power is supplied from the sub battery 33 and the engine 21 is started.
In this way, by obtaining the driver's consent or permission, it is possible to perform starting according to the driver's intention.
(10) In the engine start method according to the first embodiment, the switch for switching the engine stop function to valid or invalid is also used as a switch for confirmation.
Thus, the increase in the number of parts can be suppressed by utilizing the existing switch.

(11) In the engine starting method according to the first embodiment, power is supplied from the sub-battery 33 by connecting the sub-battery 33 in parallel with the main battery 32 to the power supply circuit 31 to which the main battery 32 is connected. Do.
Thus, by connecting the sub battery 33 to the power supply circuit 31, power can be supplied from the sub battery 33.
(12) In the engine start-up method according to the first embodiment, the relay 34 switches whether the sub-battery 33 is connected to the power supply circuit 31 or disconnected from the power supply circuit 31.
Thus, by using the relay 34, connection or disconnection of the sub-battery 33 can be switched easily and reliably.

(13) In the engine start-up method according to the first embodiment, the engine 21 is started after the sub-battery 33 is connected to the power supply circuit 31, and when the start of the engine 21 fails, the sub-battery 33 is Cut off.
Thus, by disconnecting the sub-battery 33 from the power supply circuit 31, it is possible for the user to prepare for a jump start from the external power supply.

(14) The engine starting device according to the first embodiment includes the main battery 32 and the sub-battery 33 having higher durability against repeated charging and discharging than the main battery 32. Then, the state of the main battery 32 is diagnosed. If it is determined that the electric power supplied from the main battery 32 can not start the engine 21 as a result of the diagnosis, the electric power is supplied from the sub-battery 33 to start the engine 21 next time the engine 21 is started.
As described above, when it is determined that the electric power supplied from the main battery 32 can not start the engine 21, the electric power is supplied from the sub-battery 33 to start the engine 21, thereby assisting the start of the engine 21. it can.

Second Embodiment
"Constitution"
In the second embodiment, the main battery 32 can be disconnected from the power supply circuit 31.
FIG. 6 is a block diagram of a power supply circuit in the second embodiment.
The power supply circuit 31 is a circuit that supplies power to the starter motor 22, the electrical load 25, and the electrical load 26, and includes a main battery 32, a sub-battery 33, a relay 34, and a relay 35.
Here, except for the addition of the electrical component load 26 and the relay 35, since it is the same as the first embodiment described above, the detailed description of the common parts will be omitted.

The main battery 32 and the electrical load 26 are connected in parallel.
The relay 35 is a switch that switches whether the main battery 32 and the electrical load 26 are connected to the power supply circuit 31 or disconnected from the power supply circuit 31, and is controlled by the controller 11. The relay 35 is a normally closed b contact, and connects the main battery 32 and the electrical load 26 to the power supply circuit 31 when the contacts are closed, and powers the main battery 32 and the electrical load 26 when the contacts are open. The circuit 31 is disconnected. Since the main battery 32 and the electrical load 26 are connected in parallel, even if the main battery 32 and the electrical load 26 are disconnected from the power supply circuit 31, power can be supplied from the main battery 32 to the electrical load 26. .

  The electrical load 25 is an electrical system that does not affect the performance even if the power supply voltage of the vehicle instantaneously decreases due to a large current flowing through the starter motor 22 when restarting the engine 21 from the idling stop. For example, a wiper, a headlight, an air bag, etc. On the other hand, when the electric load 26 restarts the engine 21 from the idling stop, if the power supply voltage of the vehicle instantaneously decreases due to the large current flowing through the starter motor 22, the electric load 26 is an electric system that causes problems. For example, a navigation system or audio. As described above, when restarting the engine 21 from the idling stop, the electric load of the vehicle is classified and the circuit configuration is classified according to whether the performance declines due to the instantaneous decrease of the power supply voltage of the vehicle or not. decide.

  Basically, the main battery 32 is connected to the power supply circuit 31 whether the operation of the engine 21 is stopped or the engine 21 is operated. Therefore, when the engine 21 is started according to the driver's start operation such as the driver's key operation or button operation from the state where the operation of the engine 21 is stopped, power is supplied from the main battery 32 of the lead storage battery. Will do. Also, while the engine 21 is in operation, the main battery 32 is charged with the power supplied from the alternator 24. On the other hand, when restarting the engine 21 from the idling stop, the main battery 32 is disconnected from the power supply circuit 31, and then the sub-battery 33 is connected to the power supply circuit 31 to supply power to the starter motor 22. Furthermore, even when performing the preliminary start process, after the main battery 32 is disconnected from the power supply circuit 31, the sub-battery 33 is connected to the power supply circuit 31 and power is supplied to the starter motor 22.

Next, the preliminary start process will be described.
FIG. 7 is a flowchart showing the preliminary start process.
Here, except that the processes of steps S201 to S207 are newly added, they are the same as those of the first embodiment described above, and therefore detailed description of common parts will be omitted.
When the driver performs a predetermined operation in step S114, the process proceeds to step S201.
In step S201, the main battery 32 and the electrical load 26 are disconnected from the power supply circuit 31 by opening the relay 35, and then the process proceeds to step S115.

When the engine 21 is successfully started in step S117, the process proceeds to step S202. On the other hand, when the start of the engine 21 fails, the process proceeds to step S203.
In step S202, the main battery 32 and the electrical load 26 are connected to the power supply circuit 31 by closing the relay 35, and then the process proceeds to step S118.
In step S203, it is determined whether the driver has the intention to start. For example, if the ignition remains on, it is determined that the driver has the intention to start. Here, when the driver has the intention to start, it is determined that it is necessary to try a preliminary start, and the process proceeds to step S204. On the other hand, when the driver has no intention to start, it is determined that the preliminary start is not necessary, and the process proceeds to step S207.

In step S 204, the main battery 32 and the electrical load 26 are connected to the power supply circuit 31 by closing the relay 35.
In the following step S205, the engine 21 is again cranked by the starter motor 22 to try a preliminary start using both the main battery 32 and the sub battery 33. Here, the number of times of cranking is limited, for example, a few times.

In the following step S206, it is determined whether or not the engine 21 has been successfully started by the preliminary start process. When the start of the engine 21 is successful, the process proceeds to step S118. On the other hand, when the start of the engine 21 fails, the prestart is abandoned and the process proceeds to step S121.
In step S207, the main battery 32 and the electrical load 26 are connected to the power supply circuit 31 by closing the relay 35, and then the process proceeds to step S121.
The above is the preliminary start process.

<< Operation >>
Next, the operation of the second embodiment will be described.
When restarting the engine 21 after automatic stop (temporary stop) by idling stop, the main battery 32 is disconnected from the power supply circuit 31, and then the sub battery 33 is connected to the power supply circuit 31, and only the sub battery 33 Supply power. As a result, even if automatic stop and restart of the engine 21 are repeatedly performed by idling stop, frequent charging and discharging of the main battery 32 can be suppressed, and early deterioration can be suppressed.

  Further, since the electrical load 26 is also disconnected from the power supply circuit 31 together with the main battery 32, the electrical load 26 is supplied with power only from the main battery 32. Therefore, even if the power supply voltage of the power supply circuit 31 instantaneously decreases due to the large current flowing to the starter motor 22 when restarting the engine 21 from the idling stop, the influence on the electrical load 26 can be prevented. That is, since the electric power load 26 is continuously supplied with stable power from the main battery 32, it is possible to prevent the performance from being disturbed. On the other hand, even if the power supply voltage instantaneously decreases, the electrical equipment load 25 does not pose a problem because it is not an electrical equipment system that impairs performance.

Then, when the engine 21 is started according to the driver's start operation such as the driver's key operation or button operation from the state where the operation of the engine 21 is stopped, the electric power is generated only by the main battery 32 of the lead storage battery. It will supply.
However, when the switching flag is set to fs = 1 (the determination in step S101 is “No”), power is supplied from the sub battery 33 to start the engine 21 as the preliminary start process. First, the main battery 32 and the electrical load 26 are disconnected from the power supply circuit 31 via the relay 35 (step S201). Next, after the sub-battery 33 is connected to the power supply circuit 31 via the relay 34 (step S115), the engine 21 is started (step S116).

As described above, the main battery 32 and the electrical load 26 are disconnected from the power supply circuit 31 and the backup preliminary start using only the sub-battery 33 is attempted, thereby maintaining the performance of the electrical load 26 while starting the engine 21. Can help. Also, by connecting or disconnecting the main battery 32 and the electrical load 26 via the relay 35, switching can be performed easily and reliably.
When the engine 21 is successfully started by the preliminary start using only the sub-battery 33 (the determination in step S117 is "Yes"), the main battery 32 and the electrical load 26 are connected to the power supply circuit 31 (step S202). Thus, the main battery 32 can be charged by the power of the alternator 24.

  On the other hand, when the start of the engine 21 fails even in the preliminary start using only the sub-battery 33 (the determination in step S117 is "No"), the main battery 32 and the electrical load 26 are connected to the power supply circuit 31 via the relay 35. (Step S204). Then, start of the engine 21 is tried again as preliminary start using both the sub-battery 33 and the main battery 32 (step S206). As described above, by attempting the preliminary start using both the sub-battery 33 and the main battery 32, the start of the engine 21 can be assisted in a superimposed manner.

The main battery 32 and the sub-battery 33 are connected to the power supply circuit 31 when the start of the engine 21 is successful by the preliminary start using both the sub-battery 33 and the main battery 32 (the determination in step S206 is "Yes"). Leave. On the other hand, even in the preliminary start using both the sub battery 33 and the main battery 32, when the start of the engine 21 fails (the determination in step S206 is "No"), the sub battery 33 is disconnected from the power supply circuit 31. Thereby, it is possible to prepare for jump start from the external power source by the user.
In addition, about the part common to 1st Embodiment mentioned above, the same effect shall be obtained and detailed explanation is omitted.

<< Correspondence relationship >>
Relay 35 corresponds to "a switch for the main storage battery". The electrical load 26 corresponds to the "predetermined electrical load". Steps S201 to S207 are included in the "prestarter".
<< Modification >>
In the second embodiment, when the start of the engine 21 fails as a preliminary start using only the sub battery 33, the start of the engine 21 is tried again as a preliminary start using both the sub battery 33 and the main battery 32. However, it is not limited to this. That is, when the start of the engine 21 fails as the preliminary start using only the sub-battery 33, the start of the engine 21 may be abandoned. In this case, the sub-battery 33 is disconnected from the power supply circuit 31 and the main battery 32 is connected to the power supply circuit 31 to prepare for jump start from the external power supply by the user.

"effect"
Next, the effects of the main part in the second embodiment will be described.
(1) In the engine starting method according to the second embodiment, after the main battery 32 and the electrical load 26 are disconnected from the power supply circuit 31, the sub-battery 33 is connected to the power supply circuit 31.
As described above, by disconnecting the main battery 32 and the electrical load 26 from the power supply circuit 31, the start of the engine 21 can be assisted while maintaining the performance of the electrical load 26.

(2) In the engine starting method according to the second embodiment, the relay 35 switches whether the main battery 32 and the electrical load 26 are connected to the power supply circuit 31 or disconnected from the power supply circuit 31.
Thus, by connecting or disconnecting the main battery 32 and the electrical load 26 via the relay 35, switching can be performed easily and reliably.

(3) In the engine starting method according to the second embodiment, the engine 21 is started after the sub-battery 33 is connected to the power supply circuit 31, and when the engine 21 is successfully started, the main battery 32 and the electrical load 26 are It is connected to the power supply circuit 31.
As described above, when the start of the engine 21 is successful, the main battery 32 and the electrical load 26 can be connected to the power supply circuit 31 to charge the main battery 32.

(4) In the engine starting method according to the second embodiment, the engine 21 is started after the sub-battery 33 is connected to the power supply circuit 31, and when starting of the engine 21 fails, the sub-battery 33 is It is shut off, and the main battery 32 and the electrical load 26 are connected to the power supply circuit 31.
As described above, by disconnecting the sub-battery 33 and connecting the main battery 32 and the electrical load 26, it is possible to prepare for a user's jump start from the external power supply.

(5) In the engine start-up method according to the second embodiment, the engine 21 is started after the sub-battery 33 is connected to the power supply circuit 31, and when the start of the engine 21 fails, the sub-battery 33 is used as the power supply circuit 31. In the connected state, after the main battery 32 and the electrical load 26 are connected to the power supply circuit 31, the engine 21 is tried to start again.
As described above, by attempting the preliminary start using both the sub-battery 33 and the main battery 32, the start of the engine 21 can be assisted in a superimposed manner.
Although the foregoing has been described with reference to a limited number of embodiments, the scope of rights is not limited to them, and modifications of the embodiments based on the above disclosure are obvious to those skilled in the art. Moreover, each embodiment can be arbitrarily combined and employ | adopted.

11 Controller 21 Engine 22 Starter Motor 24 Alternator 25 Electrical Load 26 Electrical Load 31 Power Circuit 32 Main Battery 33 Sub Battery 34 Relay 35 Relay

Claims (18)

Diagnose the condition of the main battery,
As a result of the diagnosis, when it is determined that the electric power supplied from the main storage battery can not start the engine, the next time when the engine is started, a secondary storage battery having higher durability against repeated charging and discharging than the main storage battery There row starting of the engine to supply power,
If there is an engine stop function to stop the engine according to the vehicle condition,
An engine starting method comprising: supplying power from the auxiliary storage battery to start the engine, and disabling the engine stop function when the engine is successfully started.   The state of the main storage battery according to the minimum voltage of the main storage battery when power is supplied from the main storage battery to start the engine, and the charge / discharge amount of the main storage battery since the engine was started The engine starting method according to claim 1, wherein:   The engine starting method according to claim 1, wherein power is supplied from the auxiliary storage battery when the auxiliary storage battery is in a predetermined charging state.   The electric power is supplied from the secondary storage battery to start the engine, and when the engine is successfully started, the driver is notified of that when the start of the engine is successful. How to start the engine. When the generator that obtains the power of the engine to generate power and charges the main storage battery with the generated power has a voltage variable function to control the generated voltage,
The electric power is supplied from the secondary storage battery to start the engine, and when the engine is successfully started, the voltage variable function is invalidated, according to any one of claims 1 to 4. How to start the engine. The engine starting method according to any one of claims 1 to 5 , wherein when the electric power is supplied from the auxiliary storage battery to start the engine, the number of times is limited. The engine starting method according to any one of claims 1 to 6 , wherein when the engine hood is open, supplying power from the auxiliary storage battery is prohibited. The engine starting method according to any one of claims 1 to 7 , wherein the driver is asked whether power is supplied from the auxiliary storage battery to start the engine. If there is an engine stop function to stop the engine according to the vehicle condition,
The engine start method according to claim 8 , wherein a switch for switching the engine stop function to enable or disable is also used as a switch for the confirmation. With respect to the main storage battery connected to power supply circuit, said main battery and said parallel by connecting the secondary battery, any one of claims 1-9, characterized by supplying electric power from said secondary battery The engine starting method as described in a term. The engine starting method according to claim 10 , wherein whether the auxiliary storage battery is connected to the power supply circuit or disconnected from the power supply circuit is switched by a switch for the auxiliary storage battery. Said secondary battery of starting of the engine after connecting to the power supply circuit, when it fails to start the engine, according to claim 10 or 11, characterized in that blocking the auxiliary battery from said power supply circuit How to start the engine. Any and then cut the main battery, and a predetermined electrical load connected in parallel with the main battery from the power supply circuit, according to claim 10-12, characterized in that connecting the secondary battery to the power supply circuit The engine starting method according to any one of the preceding claims. 14. The method according to claim 13 , wherein switching between the main storage battery and the electrical load is connected to the power supply circuit or disconnected from the power supply circuit is performed by a switch for the main storage battery. Wherein of starting of the engine the auxiliary battery after connecting to the power supply circuit, when a successful start of the engine, according to claim 13, characterized in that connecting said main battery and the electrical load on the power supply circuit Or the engine starting method as described in 14 . The engine is started after the secondary storage battery is connected to the power supply circuit, and when startup of the engine fails, the secondary storage battery is disconnected from the power supply circuit, and the main storage battery and the electrical load are connected to the power supply. The engine starting method according to any one of claims 13 to 15 , wherein the method is connected to a circuit. The engine is started after the secondary storage battery is connected to the power supply circuit, and when the start of the engine fails, the main storage battery and the electrical load are connected with the secondary storage battery connected to the power supply circuit. The engine starting method according to any one of claims 13 to 16 , wherein the engine is started again after connection to a power supply circuit. Main storage battery,
A secondary storage battery that is more durable against repeated charging and discharging than the main storage battery;
A diagnosis unit that diagnoses the state of the main storage battery;
As a result of the diagnosis by the diagnosis unit, when it is determined that the electric power supplied from the main storage battery can not start the engine, next time when the engine is started, the durability against repeated charging and discharging is higher than that of the main storage battery. And a preliminary start unit for supplying power from a secondary storage battery to start the engine .
If there is an engine stop function to stop the engine according to the vehicle condition,
An engine starting device characterized in that electric power is supplied from the auxiliary storage battery to start the engine, and the engine stop function is disabled when the engine is successfully started.

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