JP3587055B2 - Hybrid vehicle control device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for a hybrid vehicle.
[0002]
[Prior art]
Hybrid vehicles that run using both an engine that obtains (generates) driving force by burning fuel and a motor that obtains (generates) driving force by receiving power supply from a battery have already been put into practical use. . The amount of charge of the battery has a great effect on traveling, and Japanese Patent Application Laid-Open No. 9-98502 proposes a device that displays the distance that can be traveled from the current amount of battery charge. Japanese Patent Application Laid-Open No. 9-233607 discloses a device that prohibits the automatic transmission from traveling in the power mode when the charged amount of the battery is reduced.
[0003]
In a hybrid vehicle, a generator (generator) driven by the engine is provided to charge a battery serving as a voltage source of the motor using the engine. On the other hand, in a hybrid vehicle, the engine is frequently started and stopped, that is, the engine is frequently started. In order to start the engine in an extremely short time, the generator is required to generate a large driving force. Therefore, the generator driven by the engine is a large generator motor.
[0004]
[Problems to be solved by the invention]
By the way, a battery as a voltage source of a motor can store an extremely large amount of electric power, but the degree of self-discharge is considerably large. If the battery discharges and the amount of stored power drops significantly, the generator / motor cannot be operated even when power is supplied from the battery to the generator / motor, that is, the engine cannot be started. Will happen.
[0005]
For this reason, some hybrid vehicles that have been put into practical use include a small emergency motor that can be driven by a battery with a significantly reduced storage amount, a small emergency generator driven by the emergency motor, and an emergency power generator. When the generator (motor) cannot be driven when the amount of stored power in the battery (large main battery) is significantly reduced by separately mounting a small emergency battery that is charged by the machine, the emergency motor is driven. In some cases, a predetermined amount of power is stored in an emergency battery, and the generator / motor is driven by the emergency battery.
[0006]
[Problems to be solved by the invention]
As described above, when the engine is started using the emergency motor, the emergency generator and the emergency battery in order to cope with an emergency in which the charged amount of the battery is significantly reduced, the emergency battery is sufficiently charged. It takes a very long time, e.g., 10 minutes to several tens of minutes, until the engine can be started, and during this time it is practically impossible to travel. (Because there is a possibility that it becomes impossible to store enough power in the emergency battery if the vehicle runs by motor.)
[0007]
The present invention has been made in view of the circumstances described above, and its purpose is to start the engine when the charged amount of the battery is significantly reduced, while avoiding any problem even if the running itself is performed immediately. It is another object of the present invention to provide a hybrid vehicle control device capable of shortening the time until the engine is started.
[0008]
[Means for Solving the Problems]
To achieve the above object, the present invention adopts the following solution. That is, as described in claim 1 of the claims,
In a control device for a hybrid vehicle that travels using an engine that obtains driving force by burning fuel and a motor that obtains driving force by receiving power supply from a battery,
A generator / motor having a function as a generator for charging the battery driven by the engine, and a function as a starter motor for cranking the engine by receiving power supply from the battery;
A charge storage amount detecting means for detecting that the charge amount of the battery is equal to or less than a predetermined value; and stopping the engine when the charge amount of the battery is detected to be equal to or less than the predetermined value. While the motor is running, the motor is driven, and the motor is regenerated at a predetermined timing while the motor is running, and the power obtained by the regeneration is supplied to the generator / motor in preference to the storage of the battery to start the engine. Emergency control means for starting the engine by cranking;
It is provided with. Preferred embodiments based on the above solution are as described in Claims 2 and 3 in the claims.
[0009]
【The invention's effect】
According to the first aspect, when the charged amount of the battery is so low that it is impossible to drive the generator / motor, the vehicle can be driven by the motor for the time being, which is preferable in terms of securing the running. Then, the kinetic energy of the running vehicle is recovered as regenerative energy using a motor, and the generator / motor is driven by the recovered regenerative energy to start the engine (cranking required for starting). It can be done promptly.
[0010]
According to the second aspect, this is preferable in that regenerative energy is efficiently supplied to the generator / motor and the generator / motor is reliably driven.
According to the third aspect, the frequency of performing regeneration, that is, the frequency of starting the engine, is increased, which is preferable in that the engine can be started more reliably.
According to the fourth aspect, more energy can be input to cranking for starting the engine, which is preferable for more reliably starting the engine.
[0011]
According to the fifth aspect, the state in which the startability is prioritized in preference to the vibration and noise of the engine is preferable in that the engine can be started more reliably.
According to claim 6, regeneration is not performed until the vehicle speed, which indicates the kinetic energy of the vehicle, is sufficiently improved, that is, until the kinetic energy of the vehicle becomes large enough to drive the generator / motor without fail. Waiting is preferable for more reliably starting the engine.
[0012]
According to the seventh aspect, the stored amount of the battery is converted into kinetic energy for vehicle running with minimum waste, that is, the regenerative energy used for starting the engine is set to be as large as possible, which is preferable for more reliably starting the engine. It becomes.
According to the eighth aspect, at the time of braking for lowering the vehicle speed (deceleration, stop), in order to increase regenerative energy for driving the generator / motor as much as possible and to make the driver feel as little shock as possible. It will be preferable.
[0013]
According to the ninth aspect, it is preferable to perform regeneration for driving the generator / motor during braking by manual operation so that the driver does not feel a shock.
According to claim 10, the fact that the kinetic energy of the running vehicle has become sufficiently large, that is, the state in which the regenerative energy necessary for driving the generator / motor has been sufficiently obtained, has been detected by the brake. It is preferable to obtain the force and the vehicle speed as parameters easily and accurately, and to surely start the engine.
[0014]
According to claim 11, by performing the regeneration by compensating for the magnitude of the braking force and confirming that the kinetic energy of the traveling vehicle has increased to a degree sufficient to drive the generator motor by the vehicle speed, This is preferable in that the regenerative energy required to drive the generator motor is reliably obtained, and the engine is reliably started.
According to the twelfth aspect, the driver is made to clearly recognize that the special control at the time of emergency when the charged amount of the battery is greatly reduced is performed, so that the driver does not feel uncomfortable. It is preferable to make
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
In FIG. 1, 1 is an engine, and 2 is a motor. The engine 1 is an internal combustion engine that generates driving force by burning fuel stored in a fuel tank. The engine 1 is a fuel-efficient, late-closing intake type (the closing timing of the intake valve is sufficiently delayed). Stuff). The motor 2 is an electric motor that generates a driving force by receiving power supply from the battery 3, and for example, an IPM synchronous motor is used. The battery 3 is, for example, a nickel-metal hydride battery having a large storage capacity.
[0016]
The driving force of the engine 1 is transmitted to a left and right driving wheel 9 via a clutch (main clutch) 4, a torque converter 5 with a lock-up clutch, and a multi-stage transmission mechanism 6 via a driving shaft 7 and a differential gear 8. You. The drive shaft 7 is connected to (the drive shaft of) the motor 2 via an interlocking mechanism (for example, an interlocking gear mechanism) 10.
[0017]
During traveling, as described later, traveling by only the engine 1 and traveling by only the motor 2 and traveling by both the engine 1 and the motor 2 are appropriately switched according to the traveling state. Of course, the clutch 4 is engaged (connected) when traveling by the engine 1, and the clutch 4 is released (disconnected) when traveling by the motor 2 only.
[0018]
In FIG. 1, reference numeral 11 denotes a generator motor. The generator / motor 11 functions as a generator (generator) that is driven by the engine 1 to generate power, and as a starter motor that receives power supplied from the battery 3 and performs cranking for starting the engine 1. Are appropriately used. Reference numeral 12 denotes an inverter, which transfers power between the generator motor 11 and the battery 3, transfers power between the motor 2 and the battery 3, and transfers power between the motor 2 (regenerated power) and the generator motor 11. Control of the transfer of electric power in the.
[0019]
U in FIG. 1 is a control unit (controller) configured using a microcomputer, and has a CPU, a ROM, a RAM, and the like. The control unit U performs the operation control including the start of the engine 1, the on / off control of the clutch 4, the on / off control including the engagement force adjustment of the lock-up clutch of the torque converter 5, and the shift control of the transmission 6. . The control unit U controls the motor 2 (switching control of driving force generation or recovery of regenerative energy) and controls the inverter 12. The control unit U also controls the alarm 13 using a lamp, a buzzer, or a screen display.
[0020]
By the control of the inverter 12 by the control unit U, the control of the transfer of power is performed in the following manner, for example. Basically, control of power supplied from the battery 3 to the motor 2 (running control by the motor 2), control of supplying regenerative energy by the motor 2 to the battery 2 (charging control), and generation of power from the battery 3 by a generator Control to supply to the motor 11 (cranking control for starting the engine), control to supply the electric power generated by the generator motor 11 to the battery 3 (charging control), and electric power to be generated by the generator motor 11 Is supplied to the motor 2 (running control by the motor 2). Further, in an emergency, in order to start the engine 1 in an emergency when the charged amount of the battery 3 is reduced to such an extent that the generator / motor 11 cannot be driven, the regenerative energy (electric power) of the motor 2 is transferred to the battery 3 as described later. The control is also performed to supply all to the generator / motor 11 without supplying to the generator / motor 11.
[0021]
To the control unit U, in addition to the amount of power stored in the battery 3 (for example, in terms of generated voltage), signals from various sensors S1 to S3 as detection means are input. The sensor S1 detects the engine speed. The sensor S2 detects the rotation speed of the drive shaft 7, that is, the vehicle speed. The sensor S3 detects an operation force (depressing force) of the brake pedal 14.
[0022]
Next, a description will be given of a transmission form of the driving force according to the traveling state in a normal state in which the charged amount of the battery 3 is large enough to drive the generator / motor 11.
[0023]
[At start]
Traveling is performed using only the driving force of the motor 2.
"Driving at low speed"
Traveling is performed using only the driving force of the motor 2.
[When accelerating]
The vehicle travels using the driving force of both the engine 1 and the motor 2.
[During steady driving]
The driving is performed using only the driving force of the engine 1.
[0024]
[During deceleration]
The battery 3 is charged by the regeneration by the motor 2 (the clutch 4 is disconnected).
[When charging during steady running]
The clutch 4 is connected, traveling using the driving force of the engine 1 is performed, and the generator / motor 11 is driven by the engine 1 to charge the battery 3.
[When charging]
The battery 3 is charged by driving the generator / motor 11 by the engine 1 (the clutch 4 is disengaged and traveling by the engine 1 is not performed).
[0025]
Next, an emergency control in which the charged amount of the battery 3 is reduced to a predetermined value or less, that is, the state where the charged amount is reduced to a state where the generator motor 11 cannot be driven by the power supply from the battery 3 The contents will be described with reference to FIG. The following control is based on the premise that the amount of charge in the battery 3 cannot drive the generator / motor 11 but drives the motor 2 to allow the motor 2 to run. If the amount of power stored in the battery 3 is so low that it is impossible to drive the motor 2 as well, it is not a target.
[0026]
First, a flag is reset to 0 at Q (step-the same applies hereinafter) 1 in the flowchart of FIG. 2. When the flag is 0, it indicates that the engine 1 is in a stopped state. Indicates that the engine has been started. Next, in Q2, traveling using only the motor 2 is performed in response to the driver's accelerator depression operation. In Q3, it is determined whether or not the voltage of the battery 3 is equal to or less than a predetermined value Eb0. The predetermined value Eb0 is set as a value slightly smaller than the minimum voltage in consideration of a minimum voltage (amount of power storage) within a range in which the generator / motor 11 can be driven by the battery 3.
[0027]
If the determination in Q3 is YES, that is, in the case of an emergency, in Q4, the power saving traveling by the motor 2 is performed, and the alarm 13 is activated to indicate that it is an emergency. In the power-saving traveling, the required minimum traveling is made possible while increasing the vehicle speed by suppressing the acceleration of the vehicle to a predetermined value or less.
[0028]
After Q4, in Q5, it is determined whether or not the flag is 1, but initially this determination is NO, and the process proceeds to Q6. In Q6, it is determined whether or not the braking force is equal to or greater than a predetermined value FBO. If the determination in Q6 is YES, it is determined in Q7 whether the vehicle speed is equal to or higher than the predetermined vehicle speed VO. If the determination in Q7 is YES, the process shifts to Q11 in FIG. 3 to drive the generator / motor 11 utilizing the regeneration of the motor 2. The determination of Q6 and Q7 is based on whether or not the current kinetic energy of the traveling vehicle can recover sufficient energy to drive the generator / motor 11 by regeneration or braking by the motor 2 as described later. Will be determined. When the determination in Q6 is NO or when the determination in Q7 is NO, the process is shifted to Q2.
[0029]
In Q11 of FIG. 3 which is the control when YES is determined in Q7, the motor 2 is switched to the regeneration mode and the regeneration is performed. The regenerative amount at this time is set to be larger than the regenerative amount at the time of normal deceleration in which the charged amount of the battery 3 is sufficiently large. Next, in Q12, the energy regenerated by the motor 2, that is, the electric power is directly supplied to the generator / motor 11 without being supplied to the battery 3, and the generator / motor 11 is driven to crank the engine 1 Is performed.
[0030]
Subsequently, in Q13, the engine start control is performed by performing fuel supply and ignition execution so as to start the engine 1 in synchronization with the cranking of the engine 1 by the generator / motor 11. At this time, the control parameters of the engine 1 are changed so that the engine 1 can be easily started even if it is disadvantageous in terms of the vibration and noise of the engine as compared with the normal start. For example, the air-fuel ratio, the ignition timing, and the fuel pressure are changed, and the valve closing timing of the intake valve is changed if the engine has a variable intake mechanism, and the compression ratio is changed if the engine has a variable compression ratio mechanism. .
[0031]
After Q14, it is confirmed in Q15 whether or not the engine 1 has actually been started. If the determination in Q14 is YES, in Q16, the flag is set to 1 to indicate that the engine 1 has been started. Thereafter, in Q16, control is performed to drive the generator / motor 11 by the engine 1 to charge the battery 3 (the clutch 4 is disengaged and the engine 1 is operated exclusively for charging). If NO in Q14, the flag is reset to 0 in Q17, and the process returns to Q2.
[0032]
Once the engine 1 is started, the determination in Q5 becomes YES, and in this case, the process proceeds to Q14 (as long as the engine 1 is started, the process proceeds to Q16, and the charging of the battery 3 is continued. ). Note that when the determination in Q5 is YES, the process may directly proceed to Q16, but in the embodiment, the determination in Q14 is performed once in consideration of the possibility of engine stall.
[0033]
When the charging of the battery 3 in Q16 is continued, the determination of Q3 eventually becomes NO. At this time, the process proceeds to Q8, where normal control when the charged amount of the battery 3 is sufficient, that is, normal control in a state where the battery 3 can drive the generator / motor 11 is performed. At this time, the power saving travel is canceled and the alarm is also canceled.
[0034]
Here, the above-described determination of Q6 and Q7 is set from the following viewpoint. First, in FIG. 4, a constant kinetic energy line of the vehicle (a continuous line connecting points of equal kinetic energy that can be collected) is set using the vehicle speed and the braking force as parameters. That is, the kinetic energy of the vehicle that can be recovered by the brake for decreasing the vehicle speed increases as the vehicle speed increases when the braking force is the same, and increases as the braking force increases when the vehicle speed is the same. FIG. 4 shows this tendency. This is shown by isokinetic energy rays. The isokinetic energy line in FIG. 4 indicates a threshold at which electric power capable of driving the generator / motor 11 can be recovered by regeneration. In other words, the generator motor 11 can be driven by the regenerative energy when the vehicle is located in a direction where the vehicle speed or the braking force is higher than the isokinetic energy ray shown in FIG.
[0035]
The determination of Q6 and Q7 is, after all, whether or not the current kinetic energy state of the vehicle is in a kinetic energy state higher than the isokinetic energy line in FIG. In particular, the threshold value FBO is set in a range that is not so large in the braking force (the braking force by the regeneration by the motor 2) in a range where the driver does not want to apply the sudden braking (Q6). The vehicle speed on the kinetic energy line is set as the predetermined vehicle speed VO at Q7.
[0036]
Although the embodiments have been described above, the present invention is not limited to this, and includes, for example, the following cases.
(1) The regeneration by the motor 2 may be performed to drive the generator / motor 11 on condition that the braking is performed by manual operation by the driver. When the driver operates the brake, the regenerative amount of the motor 2 may be set so that a braking force having a magnitude corresponding to the brake operating force may be obtained, or the regenerative amount may be required to drive the generator / motor 11. The regenerative amount of the motor 2 may be automatically set so that a proper regenerative amount is obtained. Further, in order to obtain the driving energy of the generator / motor 11, for example, when the vehicle speed becomes equal to or higher than a predetermined vehicle speed, automatic braking by regeneration of the motor 2 may be performed. In this case, the automatic braking is activated in advance. It is preferable to warn of this.
(2) When the regeneration for driving the generator / motor 11 is performed on condition that the kinetic energy of the running vehicle is equal to or more than a predetermined value, the constant motion shown in FIG. 4 using the vehicle speed and the braking force as parameters. It can be determined that the kinetic energy of the traveling vehicle (energy that can be recovered by regeneration) is equal to or greater than the predetermined value when the vehicle is on the higher vehicle speed side and higher braking force side than the energy ray. In this case, a condition that the vehicle speed is equal to or more than a predetermined vehicle speed (for example, VO or more in FIG. 4) is further added so that regeneration for driving the generator / motor 11 is executed so that sufficient regenerative energy can be obtained. You can also.
[0037]
(3) The torque converter 5 and the transmission 6 may not be provided.
(4) In an emergency when the charged amount of the battery is equal to or less than the predetermined value, the frequency (opportunity) of regeneration by the motor 2 is increased as compared with a normal time when the charged amount of the battery is sufficiently large, so that the generator using the energy by the regeneration is used. -The opportunity which can drive the motor 11 can be increased. For example, during normal times, even when the vehicle 2 is not decelerating by the motor 2 and the speed is small (for example, when the accelerator is returned), the vehicle speed is equal to or higher than the predetermined vehicle speed and the generator motor 11 can be driven. When energy can be recovered, a larger deceleration (braking action) than in a normal state using regeneration can be performed.
[0038]
(5) During power saving traveling, it is also possible to prohibit the operation of electric devices unrelated to traveling or safety, such as air conditioners and audio equipment. Various components such as each step or sensor shown in the flowchart can be expressed by adding a name of a means to a higher-level expression of its function. In addition, the object of the present invention is not limited to what is explicitly specified, but implicitly includes providing what is expressed as substantially preferable or advantageous. Further, the present invention can be expressed as a control method.
[Brief description of the drawings]
FIG. 1 is an overall system diagram showing an embodiment of the present invention.
FIG. 2 is a flowchart showing a control example of the present invention.
FIG. 3 is a flowchart showing a control example of the present invention.
FIG. 4 is a diagram for explaining kinetic energy (regeneration energy) of a traveling vehicle.
[Explanation of symbols]
1: Engine 2: Motor 3: Battery 11: Generator / motor 13: Alarm 14: Brake pedal S1: Engine speed sensor S2: Vehicle speed sensor S3: Brake force sensor U: Control unit

Claims (12)

In a control device for a hybrid vehicle that travels using an engine that obtains driving force by burning fuel and a motor that obtains driving force by receiving power supply from a battery,
A generator / motor having a function as a generator for charging the battery driven by the engine, and a function as a starter motor for cranking the engine by receiving power supply from the battery;
Charged amount detecting means for detecting that the charged amount of the battery is equal to or less than a predetermined value,
When the charged amount detecting means detects that the charged amount of the battery is equal to or less than a predetermined value, the engine is stopped and the running by the motor is performed, and the regeneration of the motor is performed at a predetermined timing during the running by the motor. Emergency control means for starting the engine by cranking the engine by supplying the power obtained by the regeneration to the generator motor in preference to the storage of the battery,
A control device for a hybrid vehicle, comprising: In claim 1,
A control device for a hybrid vehicle, wherein electric power obtained during the regeneration is directly supplied to the generator / motor without passing through the battery to perform engine cranking. In claim 1,
When the charged amount of the battery is equal to or less than the predetermined value, a correction is performed such that the frequency of performing regeneration is increased as compared with a normal state in which the charged amount of the battery is larger than the predetermined value. Hybrid vehicle control device. In claim 1,
When the regenerative operation is performed by the emergency control means, the regenerative amount is corrected so as to be increased as compared with a normal state in which the charged amount of the battery is larger than the predetermined value. Automotive control device. In claim 1,
When the charged amount of the battery is equal to or less than the predetermined value, the engine control parameters for starting the engine improve the startability of the engine as compared with a normal state where the charged amount of the battery is larger than the predetermined value. A control device for a hybrid vehicle, wherein the control device is corrected to perform the following. In claim 1,
A control device for a hybrid vehicle, wherein the emergency control means is operated on condition that a vehicle speed becomes equal to or higher than a predetermined vehicle speed. In claim 1,
When the charged amount of the battery is equal to or less than the predetermined value, the traveling by the motor is corrected in a direction in which the power consumption of the battery is reduced as compared with a normal state in which the charged amount of the battery is larger than the predetermined value. A driving environment notification device for a vehicle. In any one of claims 1 to 7,
The control device for a hybrid vehicle, wherein the predetermined timing is set as a braking time for reducing a vehicle speed. In claim 8,
The control device for a hybrid vehicle, wherein the braking time as the predetermined timing is set as a braking time by a manual operation of a driver. In any one of claims 1 to 7,
The hybrid vehicle according to claim 1, wherein the predetermined timing is set when the kinetic energy of the vehicle, in which the vehicle speed and the braking force for reducing the vehicle speed are set as parameters, is greater than or equal to a predetermined value. Control device. In claim 10,
The control device for a hybrid vehicle, wherein the predetermined timing is further set on condition that a vehicle speed is equal to or higher than a predetermined vehicle speed. In any one of claims 1 to 11,
A control device for a hybrid vehicle, wherein an alarm is issued when the charged amount of the battery is equal to or less than the predetermined value.

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