JP2003009416A - Charge control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent useless consumption of an electric energy charged by regeneration, etc., when at least two charging modes with different charging voltage levels for a secondary battery are executed. SOLUTION: When the charging mode is switched from the regeneration mode to a generating mode, the charging voltage is gradually changed (S170-S190). Therefore, the potential difference between the terminal voltage of the battery for high voltage power supply and the charging voltage of the inverter changes almost identically. Since the counter current from the battery for the high voltage power supply to the inverter can be prevented, the useless consumption of the regeneration energy can be prevented and an improvement effect of the engine fuel consumption can be sufficiently obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge control device, and more particularly, to a charge control device for charging a secondary battery by executing at least two charge modes having different charge pressure levels. .

[0002]

2. Description of the Related Art A vehicle drive device having a structure in which a motor generator is connected to a crankshaft of an internal combustion engine (for example, Japanese Unexamined Patent Publication No. Hei-1
No. 1-147424) is known. In this technique, when the vehicle is driven by the driving force of the internal combustion engine, the secondary battery is charged by using the motor generator as a generator (referred to as "power generation mode"). Further, when the vehicle is decelerated, fuel is cut off and the running energy of the vehicle is regenerated as electric power by a motor generator as a generator to charge a secondary battery (referred to as "regeneration mode"). Further, during automatic stop of the internal combustion engine, the motor generator is used as an electric motor to drive an auxiliary machine, and at the time of automatic start, the motor generator is used as an electric motor to start the internal combustion engine or start the vehicle. There is.

In such an internal combustion engine, the secondary battery is fully charged (charge rate 100%) in the power generation mode.
However, when the regenerative mode is set, the secondary battery cannot store any more electricity, so regeneration cannot be performed and fuel consumption cannot be improved.

Therefore, in the power generation mode, the charge rate of the secondary battery must be kept at a value less than 100%, for example, 60 to 70%, except for a special charge mode such as refresh charging.

[0005]

However, in the power generation mode, the charging pressure (eg, 37.5) applied to the secondary battery in order to make the charging rate of the secondary battery 70%, for example.
V) is a charging pressure (for example, 42V) that enables a charging rate of over 70% (for example, 100%) in the regenerative mode.
Will be set lower than. For this reason, when the state in which the regeneration mode is being executed is switched to the state in which the power generation mode is being executed, the charging pressure will drop sharply.

Even when the charging pressure sharply drops in this way, the terminal voltage of the secondary battery does not drop sharply but gradually drops due to the nature of the secondary battery. Therefore, a voltage difference occurs between the terminal voltage of the secondary battery and the charging device side such as the inverter. At this time, since the charging device side is in the power generation mode, it is electrically connected to the terminal of the secondary battery. Therefore, while the terminal voltage of the secondary battery is higher than the charging voltage,
Current flows from the secondary battery to the charger side.

Therefore, until just before, the electric energy stored in the secondary battery by regenerating the vehicle running energy in the regenerative mode is wastefully consumed as heat energy in the charging device, or returns to the motor generator. A phenomenon occurs such that the output torque of the internal combustion engine unnecessarily increases. Therefore, some or all of the regenerated energy is lost, and the fuel consumption improving effect cannot be sufficiently obtained.

It is an object of the present invention to prevent wasteful consumption of electric energy charged by regeneration or the like as described above when executing at least two charge modes having different charge pressure levels for a secondary battery. It is what

[0009]

[Means for Solving the Problems] Means for achieving the above-mentioned objects and their effects will be described below. The charge control device according to claim 1, wherein the charge control device charges the secondary battery by executing at least two charge modes having different charge pressure levels with respect to the secondary battery. When the charging mode is switched from the charging mode to the charging mode of low charging pressure, the charging pressure gradual changing means for gradually changing the charging pressure is provided.

The charging pressure gradual changing means gradually changes the charging pressure when switching the charging mode from the high charging pressure charging mode to the low charging pressure charging mode. Therefore, the potential difference between the terminal voltage of the secondary battery and the charging device side is substantially the same in the process of switching from the high charging pressure charging mode to the low charging pressure charging mode and thereafter. In this way, the amount of current flowing from the secondary battery to the charging device side can be almost eliminated.

Therefore, useless consumption of electric energy can be prevented. In the charging control device according to claim 2, in the configuration according to claim 1, a power generation mode in which the secondary battery is charged at a low charging pressure using power generated by an output of a vehicle driving internal combustion engine; The charging mode gradually changing the charging pressure when switching the charging mode from the regeneration mode to the power generation mode, while executing the regeneration mode in which the battery is charged at a high charging pressure using the regenerative electric power of the running energy. It is characterized by

As described above, in the case of the secondary battery used in the vehicle driving internal combustion engine, the charging pressure gradual changing means gradually changes the charging pressure when switching the charging mode from the regeneration mode to the power generation mode. Is changing.

Therefore, in the process of switching from the high charge pressure regenerative mode to the low charge pressure power generation mode and after that, the potential difference between the terminal voltage of the secondary battery and the charging device becomes almost the same, and the secondary battery is charged. The amount of current flowing to the device side can be almost eliminated. Therefore, useless consumption of regenerative energy can be prevented, and the fuel consumption improvement effect of the internal combustion engine can be sufficiently obtained.

As a secondary effect, since the power generation load is gradually changed when the mode is switched from the regenerative mode to the power generation mode, a sudden change in the running torque is not caused and a shock to the vehicle is suppressed. it can.

According to a third aspect of the present invention, in the charging control device according to the second aspect, the charging in the power generation mode has an upper limit at an intermediate charging rate set to less than 100%, and the charging in the regenerative mode. Is provided with a charging rate control means for setting a charging rate exceeding the intermediate charging rate as an upper limit.

By setting in this way, it is possible to prevent 100% recharge of the secondary battery in the power generation mode and to effectively regenerate running energy of the vehicle in the regenerative mode. Then, after this regenerative mode, when shifting to the power generation mode, it is possible to prevent wasteful consumption of regenerative energy, and it is possible to sufficiently obtain the fuel consumption improvement effect of the internal combustion engine,
In addition, a shock to the vehicle can be suppressed.

According to a fourth aspect of the present invention, in the charge control device according to the second or third aspect, the charging pressure gradual changing means is
The charging pressure is gradually changed both when the charging mode is switched from the regeneration mode to the power generation mode and when the charging mode is switched from the power generation mode to the regeneration mode.

The charging pressure may be gradually changed even when the charging mode is switched from the power generation mode to the regeneration mode. As a result, the load on the power generation is gradually changed even when the mode is switched from the power generation mode to the regeneration mode, so that the shock to the vehicle can be suppressed.

According to a fifth aspect of the present invention, in the charge control device according to any one of the second to fourth aspects, the charging pressure gradual changing means changes the operating state of the vehicle or the operating state of the internal combustion engine for driving the vehicle. It is characterized in that the degree of gradual change is switched accordingly.

The state of charge and the degree of charge with respect to the secondary battery immediately before the mode switching differs depending on the vehicle speed, the internal combustion engine speed, and the like. Therefore, the charging pressure gradual change means switches the degree of gradual change in accordance with the running state of the vehicle or the operating state of the vehicle driving internal combustion engine, whereby the charging pressure can be gradually changed at an appropriate speed according to the situation. This makes it possible to shift the charging pressure to an appropriate state as quickly as possible, prevent wasteful consumption of regenerative energy, and sufficiently obtain the fuel consumption improvement effect of the internal combustion engine.

According to a sixth aspect of the present invention, in the charge control device according to any one of the second to fifth aspects, the motor generator that is interlocked with the rotation of the output shaft of the vehicle driving internal combustion engine causes the power generation mode and the regeneration. It is characterized by power generation in mode.

Thus, by using the motor generator as an electric motor, auxiliary machinery can be driven, the internal combustion engine can be started, and the vehicle can be run, and by using the motor generator as a generator, the above-described effects can be produced. .

In particular, since the motor generator switches to a state in which it consumes the electric energy of the secondary battery as an electric motor, it is important that the charging rate is appropriately controlled by the above-mentioned operation effects and wasteful consumption of regenerative energy is prevented. It will be

According to a seventh aspect of the present invention, in the charge control device according to the second aspect, the vehicle driving internal combustion engine is automatically stopped when the engine stop condition is satisfied, and the engine start condition is satisfied. It is characterized by having an automatic stop and start function that automatically starts when the condition is satisfied.

Even in an internal combustion engine for driving a vehicle having such an automatic stop / start function, it is possible to prevent wasteful consumption of regenerative energy, obtain a sufficient fuel consumption improvement effect of the internal combustion engine, and shock the vehicle. Can also be suppressed.

Particularly, since the internal combustion engine is frequently started by the automatic start and the electric energy of the secondary battery is frequently consumed by the electric motor such as the motor generator, the charging rate is appropriately controlled by the above-described effects. Therefore, it is important to have an operational effect capable of preventing wasteful consumption of regenerative energy.

In the charging control device according to the eighth aspect, in the configuration according to the sixth aspect, both the internal combustion engine for driving the vehicle and the motor generator are used for running the vehicle, and the vehicle is operated according to the running state of the vehicle. It is characterized in that the vehicle is driven by the driving force of either or both of the driving internal combustion engine and the motor generator.

As described above, even when the internal combustion engine and the motor generator as an electric motor are both used for vehicle traveling such as a hybrid car system,
The charge rate can be appropriately controlled, useless consumption of regenerative energy can be prevented, the fuel efficiency of the internal combustion engine can be sufficiently improved, and the shock to the vehicle can be suppressed.

In particular, in such a system, since the state of consuming the electric energy of the secondary battery frequently occurs, the charging rate is appropriately controlled by the above-mentioned effects and the wasteful consumption of the regenerative energy is prevented. The effect that can be achieved becomes important.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] FIG. 1 is a system configuration diagram of a vehicle internal combustion engine and a control device thereof to which the above-described invention is applied. Here, a gasoline engine (hereinafter referred to as “engine”) 2 is used as the internal combustion engine. The engine 2 is a cylinder injection type gasoline engine in which fuel is directly injected from a fuel injection valve into a combustion chamber and ignited by an ignition plug.

Here, the output of the engine 2 is the engine 2
Crankshaft 2a to torque converter 4 and automatic transmission (automatic transmission: "A /
(Hereinafter referred to as “T”) 6 and is output to the output shaft 6a side and finally transmitted to the wheels. Separately from this, the output of the engine 2 is transmitted to the belt 14 via the pulley 10 connected to the crankshaft 2a. And this belt 1
The output transmitted by means of 4 causes another pulley 16, 18
Is rotated. The pulley 10 has an electromagnetic clutch 10a.
Is provided and is turned on (connected) and turned off (interrupted) as needed, so that transmission / non-transmission of output can be switched between the pulley 10 and the crankshaft 2a.

Of the pulleys 16 and 18, the pulley 16 is connected to the rotary shaft of the auxiliary machine 22 and can be driven by the rotational force transmitted from the belt 14. The auxiliary device 22 corresponds to, for example, an air conditioner compressor, a power steering pump, an engine cooling water pump, or the like. Although shown as one auxiliary device 22 in FIG. 1, there are actually one or more of an air conditioner compressor, a power steering pump, an engine cooling water pump, and the like. Each pulley is provided so as to rotate in conjunction with the belt 14. In the first embodiment, it is assumed that the auxiliary machine 22 is provided with an air conditioner compressor, a power steering pump, and an engine cooling water pump.

A motor generator (hereinafter referred to as “M / G”) 26 is linked to the belt 14 by a pulley 18. The M / G 26 functions as a generator as necessary (hereinafter, referred to as “power generation mode” or “regeneration mode”), so that the rotational force from the engine 2 or the wheels transmitted via the pulley 18 is converted into electric energy. Convert to. Further, the M / G 26 functions as a motor (electric motor) as necessary (hereinafter referred to as “drive mode”) to rotate one or both of the engine 2 and the auxiliary machine 22 via the pulley 18 and the belt 14. .

Here, the M / G 26 is electrically connected to the inverter 28. When the M / G 26 is set to the power generation mode or the regenerative mode, the eco-run ECU 40 described later is used.
The inverter 28 controlled by adjusts the charging pressure and the power generation amount (power generation load) by switching,
The M / G 26 supplies electricity to a battery 30 (corresponding to a secondary battery) for a high-voltage power supply (here, 36V) and to a low-voltage power supply (here, 12V) battery 34 via a DC / DC converter 32. To charge the energy,
Further, it is switched so as to be a power source for the ignition system, meters, each ECU and the like.

Further, the inverter 28 is an eco-run ECU.
40, the high-voltage power supply battery 30 is charged so that the charging rate is 70% (corresponding to the intermediate charging rate) at the charging voltage Vl in the power generation mode. Further, in the regenerative mode, the high-voltage power supply battery 30 can be charged with the charging voltage Vh (Vh> Vl) up to the charging rate of 100%. This realizes the function as the charging rate control means.

When power is not being generated by the M / G 26, the high-voltage power supply battery 30 and the low-voltage power supply battery 34 are connected via the DC / DC converter 32, so that the high-voltage power supply battery 30 side The low voltage power supply battery 34 is configured to constantly increase the charging rate to 100% by the electric power supplied from.

When the M / G 26 is set to the drive mode,
The inverter 28 is a battery 30 for a high voltage power source which is a power source.
The M / G 26 is driven by supplying power from the M / G 26 to the M / G 26. As a result, through the pulley 18 and the belt 14, the auxiliary machine 22 is rotated when the engine is stopped, and the crankshaft 2a is rotated as needed when the engine is automatically started, automatically stopped, or started. At this time, the inverter 28 can adjust the rotation speed of the M / G 26 by adjusting the supply of electric energy from the high-voltage power supply battery 30.

A starter 36 is provided to start the engine 2 during cold starting. This starter 36
The electric power is supplied from the low-voltage power supply battery 34, and the ring gear can be rotated to start the engine 2.

The A / T 6 is provided with an electric hydraulic pump 38 which is supplied with electric power from the low-voltage power supply battery 34, and supplies hydraulic oil to the hydraulic control section inside the A / T 6. Using this hydraulic oil, the control valve in the hydraulic control unit adjusts the operating state of the clutch, brake and one-way clutch inside the A / T 6, and switches the shift state as necessary.

The eco-run ECU 40 executes the above-mentioned control such as switching on / off of the electromagnetic clutch 10a, mode control of the M / G 26 and the inverter 28, control of the starter 36, and control of the charging rate for the batteries 30, 34. Further, the drive on / off of the auxiliary machine 22 excluding the water pump, the drive control of the electric hydraulic pump 38, the shift control of the A / T 6, the fuel injection control by the fuel injection valve 42, the opening control of the throttle valve 46 by the electric motor 44. The exhaust gas recirculation (EGR) valve opening control and other engine controls are executed by the engine ECU 48. In addition, VSC (Vehicle Stability Control)-
Since the ECU 50 is provided, automatic control of the brake on each wheel is also executed.

The eco-run ECU 40 detects the rotation speed of the rotation shaft of the M / G 26 from the rotation speed sensor built in the M / G 26, the presence / absence of activation of the economy running system by the driver from the eco-run switch, and other data. ing. Here, the economy running system (hereinafter abbreviated as "eco-run system") means that the internal combustion engine is automatically stopped when the vehicle is stopped by the starter switch or when the vehicle is stopped at an intersection or the like in order to improve fuel economy. Is an automatic stop / start system that automatically starts an internal combustion engine at the time of start operation to enable the vehicle to start.

Further, the engine ECU 48 opens the engine cooling water temperature THW from the water temperature sensor, the accelerator opening ACCP from the accelerator opening sensor, the steering angle θ of the steering from the steering angle sensor, the vehicle speed SPD from the vehicle speed sensor, and the throttle opening from the throttle opening sensor. Degree TA, the shift position sensor to the shift position SHFT, the engine speed sensor to the engine speed NE, the intake pressure sensor to the intake pressure PM, the auto air conditioner to the operating state, the air-fuel ratio sensor to the air-fuel ratio A / F appearing in the exhaust gas component, etc. Is detected for engine control, etc. The VSC-ECU 50 also detects the presence / absence of depression of the brake pedal from the brake switch and other data for braking control and the like.

The ECUs 40, 48 and 50 are
It is composed mainly of a microcomputer, and CP is set according to the program written in the internal ROM.
U executes necessary arithmetic processing and executes various controls based on the arithmetic result. These arithmetic processing results and the data detected as described above are used for the ECUs 40, 48, 5
It is possible to communicate and exchange between 0s, and it is possible to execute control by interlocking with each other.

The eco-run ECU 40 executes the eco-run system as described above. While the engine 2 is automatically stopped by the eco-run system, the electromagnetic clutch 10a is disengaged, and the electric energy stored in the high-voltage power supply battery 30 is used in response to the air-conditioner drive request or the power steering drive request.
26 is driven to rotate the air conditioner compressor and the power steering pump. Further, when the automatic start condition is satisfied during such automatic stop, the automatic start process is executed to connect the electromagnetic clutch 10a, and the M / G 26 using the electric energy of the high voltage power source battery 30 is used. The vehicle is started by driving and the engine 2 is automatically started.

Further, the engine ECU 48 controls the combustion mode so as to execute stratified charge combustion at low load and low rotation speed and to perform homogeneous combustion at other times of operation or at the time of starting or immediately after starting, depending on the engine operating state. There is. When the combustion mode is set to the stratified charge combustion, the throttle valve 46 is almost fully opened regardless of the degree of the accelerator opening ACCP, and the amount of fuel considerably smaller than the stoichiometric air-fuel ratio with respect to the intake air is compressed. It is controlled to be injected in the latter period.
As a result, at the ignition timing, a stratified combustion is performed by igniting a rich air-fuel mixture that exists in the vicinity of the spark plug and can be ignited. On the other hand, when the combustion mode is set to the homogeneous combustion, the opening of the throttle valve 46 is adjusted according to the degree of the accelerator opening ACCP, and the amount becomes the theoretical air-fuel ratio (in some cases, becomes richer than the theoretical air-fuel ratio). Amount of fuel is controlled to be injected during the intake stroke. As a result, at the ignition timing, a homogeneous air-fuel mixture having a stoichiometric air-fuel ratio occupying the entire combustion chamber (in some cases, richer than the stoichiometric air-fuel ratio) is ignited to perform homogeneous combustion.

Next, the charging pressure setting process for charging the high-voltage power supply battery 30 by the power generation of the M / G 26 will be described. This process is shown in the flowchart of FIG. This process is repeatedly executed by the eco-run ECU 40 in a time cycle. The steps in the flowchart corresponding to the individual processing contents are represented by "S ~".

When the charging pressure setting process is started, first, M
It is determined whether or not the mode has been changed for / G26 (S110). If there is no mode change (S1
10 is "NO"), and then it is determined whether or not the current mode is the power generation mode (S120). Here, if the current mode is not the power generation mode (“NO” in S120), it is next determined whether or not the current mode is the regenerative mode (S13).
0). Here, if the current mode is not the regenerative mode (“NO” in S130), this process is temporarily terminated as it is.

On the other hand, if there is a mode change ("YES" in S110), it is next determined whether or not the regeneration mode is changed to the power generation mode (S140). If it is not the change from the regeneration mode to the power generation mode (“NO” in S140), then it is determined whether or not the power generation mode is changed to the regeneration mode (S150). If it is not the change from the power generation mode to the regeneration mode (“NO” in S150), the present process is temporarily terminated.

If a mode change from the regenerative mode to the power generation mode occurs ("YES" in S110, S
In "140", "YES"), the gradual change step voltage width dV is calculated from the map according to the traveling state of the vehicle, here the vehicle speed SPD (S160), and this processing is once terminated. That is, in the regenerative mode, the M / G 26 is rotated by the traveling energy of the vehicle to generate electric power to charge the high-voltage power supply battery 30, and the charging voltage performed after this is set according to the charging state immediately before this. An appropriate step voltage width dV for gradual change is set at the time of reduction. The map in this case is set in advance by an experiment and is stored in the ROM of the eco-run ECU 40.
It is stored in.

In the next control cycle, since there is no mode change ("NO" in S110), it is determined whether or not the current mode is the power generation mode (S120). Since the power generation mode is set after the mode is changed here (S120
Then, it is determined whether or not the charge pressure control amount Vx is set to a voltage higher than the charge pressure Vl in the power generation mode (S170). Immediately after switching from the regeneration mode to the power generation mode, the charging pressure control amount Vx remains the charging pressure Vh in the immediately preceding regeneration mode, and Vh (42V in the present embodiment)> Vl (in the present embodiment 37.5V)
Therefore, Vx = Vh> Vl (“YES” in S170). Therefore, as shown in the following Expression 1, the current charging pressure control amount Vx is subtracted by the gradual change step voltage width dV calculated in step S160 to set a new charging pressure control amount Vx (S180). .

[0051]

[Formula 1] Vx ← Vx−dV [Equation 1] In this way, this processing is temporarily terminated. As a result, the eco-run ECU 40 uses the electric power generated by the M / G 26,
The inverter 2 is configured to adjust the charging pressure to the charging pressure control amount Vx reduced by the step voltage width dV for gradual change from the previous control cycle and charge the high-voltage power supply battery 30.
Adjust 8.

After that, when the power generation mode continues (S110
“NO” in step S120, “YES” in step S120), and as long as Vx> Vl (“YES” in step S170), the charging pressure control amount Vx is reduced by the equation 1 (step S180), and the high-voltage power supply battery 30 is charged. The voltage is gradually reduced.

When the condition of Vx> Vl is no longer satisfied as a result of the repeated gradual change of the charging pressure control amount Vx ("NO" in S170), the charging pressure control amount V is then exceeded.
The charge pressure Vl for the power generation mode is set to x (S19
0), this processing is ended once. After that, as long as the power generation mode continues (“NO” in S110, “YE” in S120).
S ”), and“ NO ”is determined in step S170 and step S190 is executed, so the charge pressure control amount Vx is maintained at the charge pressure Vl in the power generation mode.

Next, when the mode is changed from the power generation mode to the regeneration mode ("YES" in S110, S1
"NO" at 40, "YES" at S150), engine 2
Of the engine speed NE, here, the step voltage width dV for gradual change is calculated from the map according to the engine speed NE (S20
0), this processing is ended once. That is, when shifting from the power generation mode to the regeneration mode, the upper limit of the charging rate of the high-voltage power supply battery 30 changes from 70% to 100%, and the electric load increases. Therefore, there is a possibility that the running torque may suddenly change and the vehicle may be shocked due to an increase in the power generation load. In the present embodiment, in order to prevent this shock, an increase in the power generation load is gradually changed by setting an appropriate step change width dV for gradual change in accordance with the engine speed NE. The map in this case is set in advance by an experiment and stored in the ROM of the eco-run ECU 40.

In the next control cycle, since there is no mode change (“NO” in S110), it is determined whether or not the current mode is the power generation mode (S120). Since the regenerative mode is set after the mode is changed here (S120
"NO"), and then it is determined whether or not the current mode is the regeneration mode (S130). Since it is currently in the regenerative mode (“YES” in S130), the charging pressure control amount Vx is next.
Is determined to be lower than the charging voltage Vh in the regeneration mode (S210). Immediately after switching from the power generation mode to the regenerative mode, the charging pressure control amount V
x is the charging pressure Vl in the immediately preceding power generation mode, and Vl <V
Since h, Vx = Vl <Vh (S210
And "YES"). Therefore, as shown in the following Expression 2, the current charging pressure control amount Vx is added to the gradual change step voltage width dV calculated in step S200 to set a new charging pressure control amount Vx (S220). .

[0056]

[Formula 2] Vx ← Vx + dV [Equation 2] In this way, this processing is temporarily terminated. As a result, the eco-run ECU 40 uses the electric power generated by the M / G 26,
The inverter 2 is configured to charge the high-voltage power supply battery 30 by adjusting the charging pressure to the charging pressure control amount Vx increased by the step voltage width dV for gradual change from the previous control cycle.
Adjust 8.

After that, if the power generation mode continues (S110
"NO" in step S120, "NO" in step S120, "YE" in step S130.
S ”), as long as Vx <Vh (“ YE ”in S210)
S ”), the charging pressure control amount Vx is increased by the equation 2 (S220), and the charging pressure for the high-voltage power supply battery 30 is gradually increased.

When the condition of Vx <Vh is no longer satisfied as a result of repeating such gradual change of the charging pressure control amount Vx ("NO" in S210), the charging pressure control amount V is then changed.
The charge pressure Vh for the regenerative mode is set to x (S23
0), this processing is ended once. After that, as long as the regenerative mode continues (“NO” in S110, “NO” in S120,
"YES" in S130), "NO" in step S210
Since it is determined that step S230 is executed, the charging pressure control amount Vx is maintained at the charging pressure Vh in the regenerative mode.

An example of the charging pressure setting process (FIG. 2) is shown in the timing chart of FIG. 3 (A). If the power generation mode is changed to the regeneration mode at time t0, the charging pressure control amount Vx gradually increases from the charging pressure Vl for the power generation mode to the charging pressure Vh for the regeneration mode. Also, when the regeneration mode is shifted to the power generation mode, the charging pressure control amount V
x gradually decreases from the charging pressure Vh for the regeneration mode to the charging pressure Vl for the power generation mode.

As shown in FIG. 3B as a comparative example, when the power generation mode is changed to the regeneration mode (time t1
0), when the charging pressure control amount Vx is immediately switched from the charging pressure Vl for the power generation mode to the charging pressure Vh for the regeneration mode, the battery terminal voltage immediately rises. However, when the charging pressure control amount Vx is immediately switched from the charging pressure Vh for the regeneration mode to the charging pressure Vl for the power generation mode when the regeneration mode is switched to the power generation mode (time t11), the battery terminal voltage immediately decreases. There is nothing to do and time t11 to t
It gradually decreases between 12. Therefore, as indicated by the hatching, the charging voltage (Vx = V
l) becomes lower than the terminal voltage of the high-voltage power supply battery 30. Therefore, backflow of current from the high-voltage power supply battery 30 to the inverter 28 side is caused.

In the above structure, the charging pressure setting process (FIG. 2) corresponds to the process as the charging pressure gradual changing means. According to the first embodiment described above, the following effects can be obtained.

(A). In the charging pressure setting process (FIG. 2), the charging pressure is gradually changed when the charging mode is switched from the regeneration mode to the power generation mode. Therefore, the potential difference between the terminal voltage of the high-voltage power supply battery 30 and the charging voltage of the inverter 28 remains almost the same. Therefore, the voltage difference shown by hatching in FIG.
Since it is possible to prevent current backflow from the high-voltage power supply battery 30 to the inverter 28 side, it is possible to prevent wasteful consumption of regenerative energy, and it is possible to sufficiently obtain the fuel consumption improvement effect of the engine 2.

(B). The charging pressure is gradually changed when the charging mode is switched from the regeneration mode to the power generation mode, and the charging pressure is gradually changed when the charging mode is switched from the power generation mode to the regeneration mode. Therefore, during both the mode switching from the regeneration mode to the power generation mode and the mode switching from the power generation mode to the regeneration mode, a sudden change in the traveling torque is not caused, and a shock to the vehicle can be suppressed.

(C). The gradual change step voltage width dV is set by the vehicle speed SPD by reflecting the state of charge and the degree of charge of the high-voltage power supply battery 30 immediately before the mode is switched from the regenerative mode to the power generation mode. For this reason,
The charging pressure can be gradually changed at an appropriate speed according to the state of charge and the degree of charging. As a result, the charging pressure control amount Vx can be shifted to an appropriate state as quickly as possible, and
It is possible to prevent the reverse flow of electric current, prevent wasteful consumption of regenerative energy, and obtain a sufficient fuel efficiency improvement effect of the engine 2.

(D). Here, the M / G 26 is used as an electric motor for generating electricity and for driving an auxiliary machine, starting the engine, and running the vehicle as an electric motor. Then, the eco-run system executes automatic stop and automatic start. Thus, the engine 2 is frequently started by the eco-run system, and the M / G 26 frequently consumes the electric energy of the high-voltage power supply battery 30.
From this, the effect of controlling the charging rate of the high-voltage power supply battery 30 appropriately by the above-described effect and preventing the wasteful consumption of regenerative energy becomes particularly important.

[Other Embodiments] In the charging pressure setting process (FIG. 2), the charging pressure is gradually changed both when the regeneration mode is switched to the power generation mode and when the power generation mode is switched to the regeneration mode. However, the gradual change of the charging pressure may be executed only when the regeneration mode is switched to the power generation mode. In this case as well, wasteful consumption of regenerative energy can be prevented, and the fuel consumption improvement effect of the engine 2 can be sufficiently obtained. Further, it is possible to prevent a shock when shifting from the regenerative mode to the power generation mode.

Step S1 of the charging pressure setting process (FIG. 2)
In S60 and S200, the gradual change step voltage width dV is set according to the running state of the vehicle such as the vehicle speed SPD or the engine operating state such as the engine speed NE, but may be a fixed value. In this case, steps S160 and S200
Can be a common value.

In the above embodiment, the engine 2
The driving force was transferred between the M / G 26 and the M / G 26.
It can also be applied to a vehicle of a hybrid system in which the vehicle is driven by switching or using together.

In the above-mentioned embodiment, the M / G 26 which also serves as an electric motor is used as the generator, but the present invention can be applied to the case where a dedicated generator is used.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a vehicle internal combustion engine and its control device according to a first embodiment.

FIG. 2 is a flowchart of a charging pressure setting process executed by the eco-run ECU according to the first embodiment.

FIG. 3 is a timing chart showing an example of the process of the first embodiment and a comparative example.

[Explanation of symbols]

2 ... Engine, 2a ... Crankshaft, 4 ... Torque converter, 6 ... A / T, 6a ... Output shaft, 10 ... Pulley, 10a
... electromagnetic clutch, 14 ... belt, 16, 18 ... pulley,
22 ... Auxiliary equipment, 26 ... M / G, 28 ... Inverter, 30 ...
High-voltage power supply battery, 32 ... DC / DC converter, 3
4 ... Battery for low voltage power supply, 36 ... Starter, 38 ... Electric hydraulic pump, 40 ... Eco-run ECU, 42 ... Fuel injection valve, 44 ... Electric motor, 46 ... Throttle valve, 48
... engine ECU, 50 ... VSC-ECU.

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Claims (8)

[Claims] 1. A charging control device for charging a secondary battery by executing at least two charging modes with different charging pressure levels, the charging control device comprising a charging mode from a high charging pressure to a low charging mode. A charging control device comprising a charging pressure gradual changing means for gradually changing the charging pressure when switching the charging mode to the voltage charging mode. 2. The structure according to claim 1, wherein the secondary battery is charged at a low charging pressure using electric power generated by the output of a vehicle driving internal combustion engine, and regenerated by running energy of the vehicle. While performing a regenerative mode of charging at a high charging pressure using electric power, the charging pressure gradual changing means gradually changes the charging pressure when switching the charging mode from the regenerative mode to the power generation mode. Charge control device. 3. The structure according to claim 2, wherein the charging in the power generation mode has an upper limit of an intermediate charging rate set to less than 100%, and the charging in the regenerative mode exceeds the intermediate charging rate. A charging control device comprising a charging rate control unit having a rate as an upper limit. 4. The configuration according to claim 2 or 3, wherein the charging pressure gradual changing means switches a charging mode from the regeneration mode to the power generation mode and a charging mode from the power generation mode to the regeneration mode. In both cases, the charging control device is characterized in that the charging pressure is gradually changed. 5. The charging pressure gradual changing means according to claim 2, wherein the charging pressure gradual changing means changes the degree of gradual change according to a running state of the vehicle or an operating state of the vehicle driving internal combustion engine. A charging control device characterized by switching. 6. The structure according to any one of claims 2 to 5, wherein power is generated in the power generation mode and the regenerative mode by a motor generator that is interlocked with rotation of an output shaft of the vehicle driving internal combustion engine. A charging control device characterized by. 7. The automatic driving system according to claim 2, wherein the vehicle-driving internal combustion engine automatically stops when an engine stop condition is satisfied, and automatically starts when an engine start condition is satisfied. A charging control device having a stop / start function. 8. The vehicle driving internal combustion engine and the motor generator according to claim 6, wherein both the vehicle driving internal combustion engine and the motor generator are used for driving the vehicle, and the vehicle driving internal combustion engine and the motor generator are used according to a running state of the vehicle. A charging control device that drives the vehicle to travel by the driving force of either or both of the above.