JP2009298269A - Control device for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine propriety of companion turning of an internal combustion engine under the consideration of the charging state of a battery concerning the control device of a hybrid vehicle. <P>SOLUTION: An electric vehicle (EV) mode in which a motor is made to generate driving torque in a state that fuel supply to an internal combustion engine is stopped and a hybrid vehicle (HV) mode in which the internal combustion is made to generate the driving torque are switched as necessary. This control device of a hybrid vehicle includes a mechanism for varying the revolving speed of the internal combustion engine under the EV mode. The charging state of a battery is detected (steps 100, 104), and when the charging state of the battery is satisfactory, the companion turning of the internal combustion engine 10 is performed under the EV mode (step 106), and when the charging state is not satisfactory, the companion turning of the internal combustion engine is inhibited (step 102). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hybrid vehicle control apparatus, and more particularly to a hybrid vehicle control apparatus having a function of switching between an electric vehicle mode using only a motor as a power source and a hybrid vehicle mode using an internal combustion engine as a power source.

  Conventionally, as disclosed in Patent Document 1 below, a hybrid vehicle including an internal combustion engine and a motor is known as a power source. In this vehicle, the combustion stop of the internal combustion engine is required in the electric vehicle mode using only the motor as a power source. At this time, in the conventional vehicle, the fuel supply to the internal combustion engine is stopped, and the motor is controlled to rotate the internal combustion engine at a desired engine speed.

  For example, when an acceleration request is generated during traveling in the electric vehicle mode, a shift to the hybrid vehicle mode using the internal combustion engine as a power source is required. If the internal combustion engine is operating at an appropriate speed during the transition, acceleration response will be better and noise and vibration will be reduced compared to when the internal combustion engine is stopped. Can do. Therefore, according to the conventional hybrid vehicle, it is possible to switch from the electric vehicle mode to the hybrid vehicle mode smoothly and with good responsiveness.

International Publication WO2007 / 060853A1 JP 2004-324442 A

  By the way, accompanying the internal combustion engine with a motor involves power consumption. For this reason, it is desirable to perform such rotation in consideration of the state of charge of the battery. In addition, the above-mentioned turn is not effective until there is a switch from the electric vehicle mode to the hybrid vehicle mode. For this reason, it is desirable to rotate the internal combustion engine in consideration of the frequency of such switching.

  However, in the conventional hybrid vehicle described above, the internal combustion engine is rotated without considering the state of charge of the battery and the frequency of mode switching. In this regard, this vehicle still has room for improvement with regard to the rotation of the internal combustion engine.

  The present invention has been made to solve the above-described problems, and provides a control device for a hybrid vehicle that rotates the internal combustion engine in consideration of the state of charge of the battery and the frequency of mode switching. Objective.

In order to achieve the above object, a first invention is a control device for a hybrid vehicle including an internal combustion engine and a motor,
A battery capable of transferring power to and from the motor;
EV realizing means for realizing an electric vehicle mode in which a driving torque is generated in the motor in a state where fuel supply to the internal combustion engine is stopped;
HV realization means for realizing a hybrid vehicle mode for generating a driving torque in the internal combustion engine;
Engine speed changing means for changing the engine speed under the electric vehicle mode;
Charge state detection means for detecting the charge state of the battery;
Under the electric vehicle mode, the engine speed changing means for controlling the engine speed changing means based on the state of charge of the battery; and
It is characterized by providing.

In a second aspect based on the first aspect, the engine speed varying means includes a gear ratio variable gear mechanism interposed between a crankshaft of the internal combustion engine and a rotation shaft of the motor,
The accompanying rotation speed control means controls the gear ratio based on a state of charge of the battery.

In a third aspect based on the first aspect, the engine speed varying means includes a clutch mechanism interposed between a crankshaft of the internal combustion engine and a rotation shaft of the motor.
The follow-up rotation speed control means switches between a connected state and a non-connected state of the clutch mechanism based on the state of charge of the battery.

In a fourth aspect based on the first aspect, the charge state detection means includes a charge amount detection means for detecting a charge amount of the battery.
When the charge amount is greater than or equal to a predetermined value, the accompanying rotation speed control means has a higher engine speed under the electric vehicle mode than when the charge amount is less than the predetermined value. Thus, the engine speed variable means is controlled.

Further, a fifth aspect of the invention is the first or fourth aspect of the invention, wherein the charge state detection means includes a charge amount change tendency detection means for detecting a change tendency of the charge amount of the battery,
The follow-up rotation speed control means is more effective in the electric vehicle mode when the change tendency of the charge amount is on the increase side than the determination criterion, compared with the case where the change tendency is on the decrease side with respect to the determination criterion. The engine speed changing means is controlled so that the engine speed below increases.

According to a sixth aspect of the invention, in any one of the first, fourth and fifth aspects of the invention, the accompanying electric power required to rotate the internal combustion engine at a desired speed under the electric vehicle mode is acquired. Equipped with accompaniment power acquisition means,
When the accompanying power is less than or equal to a predetermined value, the accompanying rotation speed control means has an engine speed under the electric vehicle mode as compared with a case where the accompanying power exceeds the predetermined value. The engine speed variable means is controlled so as to be higher.

A seventh invention is a control device for a hybrid vehicle comprising an internal combustion engine and a motor,
EV realizing means for realizing an electric vehicle mode in which a driving torque is generated in the motor in a state where fuel supply to the internal combustion engine is stopped;
HV realization means for realizing a hybrid vehicle mode for generating a driving torque in the internal combustion engine;
Engine speed changing means for changing the engine speed under the electric vehicle mode;
Switching frequency detection means for detecting the switching frequency from the electric vehicle mode to the hybrid vehicle mode;
When the switching frequency is equal to or higher than a predetermined value, the engine speed variable means is configured so that the engine speed under the electric vehicle mode is higher than when the switching frequency is less than the predetermined value. A rotation speed control means for controlling
It is characterized by providing.

  According to an eighth aspect based on the seventh aspect, the switching frequency detection means calculates the switching frequency based on a switching history from the electric vehicle mode to the hybrid vehicle mode in a past predetermined period. It is characterized by.

Further, a ninth invention comprises a switching frequency predicting means for predicting a switching frequency from the electric vehicle mode to the hybrid vehicle mode in the seventh invention,
The accompanying rotation speed control means controls the engine speed variable means based on the detection result and the prediction result of the switching frequency.

Further, a tenth aspect of the invention is the ninth aspect of the invention, comprising a navigation device that acquires information relating to the traveling environment of the vehicle,
The switching frequency predicting means predicts the switching frequency based on the traveling environment.

  According to the first aspect, the engine speed given to the internal combustion engine under the electric vehicle mode can be controlled based on the state of charge of the battery. For this reason, according to the present invention, it is possible to cause a follow-up in preparation for switching to the hybrid vehicle mode within a range that does not unduly deteriorate the state of charge of the battery.

  According to the second invention, the engine speed applied to the internal combustion engine under the electric vehicle mode is controlled by changing the gear ratio of the gear mechanism interposed between the crankshaft of the internal combustion engine and the rotation shaft of the motor. can do.

  According to the third aspect of the present invention, by switching connection / disconnection of the clutch mechanism interposed between the crankshaft of the internal combustion engine and the rotation shaft of the motor, It is possible to switch to a state where no rotation occurs.

  According to the fourth aspect of the invention, by associating the charge amount of the battery with the rotational speed of the internal combustion engine, a large amount of electric power is consumed by the rotation of the internal combustion engine under a situation where the charge amount is small. Can be prevented.

  According to the fifth aspect of the present invention, by causing the change in the charge amount of the battery to correspond to the rotational speed of the internal combustion engine, a large amount of rotation is caused by the rotation of the internal combustion engine in a situation where the charge amount is greatly reduced. It is possible to prevent power consumption.

  According to the sixth aspect of the invention, when the accompanying electric power required to rotate the internal combustion engine is small, a high accompanying rotational speed is set to the internal combustion engine during the electric vehicle mode as compared with the case where the electric power is large. Can be given. According to the above processing, it is possible to prevent the accompanying rotation from being unnecessarily restricted under a situation where the accompanying power is low.

  According to the seventh aspect, when the frequency of switching from the electric vehicle mode to the hybrid vehicle mode is high, a high rotational speed can be given to the internal combustion engine during the electric vehicle mode. For this reason, according to the present invention, it is possible to avoid the internal combustion engine from being unnecessarily rotated in a situation where the merit of the internal combustion engine cannot be obtained so much.

  According to the eighth aspect, by calculating the switching frequency based on the switching history in the past predetermined period, it is possible to accurately reflect the actual switching frequency in the contents of the follow-up control.

  According to the ninth aspect of the invention, in addition to being able to reflect the detection result of the switching frequency from the electric vehicle mode to the hybrid vehicle mode in the contents of the turning control, the prediction result of the switching frequency is also sent to the turning control. Can be reflected in the contents of

  According to the tenth aspect, the switching frequency from the electric vehicle mode to the hybrid vehicle mode can be predicted with good accuracy from the traveling environment acquired by the navigation device.

Embodiment 1 FIG.
[System Configuration of Embodiment 1]
FIG. 1 is a diagram for illustrating a configuration of a hybrid vehicle according to a first embodiment of the present invention. In FIG. 1, each component is connected by four types of lines. Of these lines, the thin line is the “signal line”, the solid black line is the “power transmission path”, the combination of the straight line and the sine curve is the “AC power line”, and the white double line is the “DC power line” Are shown respectively.

  The system of this embodiment includes an internal combustion engine 10. The crankshaft of the internal combustion engine 10 is connected to the first rotation system of the power distribution mechanism 12. The power distribution mechanism 12 has three rotating systems. These rotating systems are connected to each other through a gear mechanism inside the power distribution mechanism 12.

  A rotation shaft of a motor generator (hereinafter referred to as “MG”) 14 is connected to the second rotation system of the power distribution mechanism 12. The MG 14 functions as a motor when supplied with power from the outside, and functions as a generator when torque is applied to its rotating shaft.

  A rotation shaft of the motor 16 is connected to the third rotation system of the power distribution mechanism 12. The rotating shaft of the motor 16 is also connected to the power take-off gear of the speed reducer 18. The speed reducer 18 has a gear mechanism therein, and the power take-out gear and the wheel shaft 20 are connected via the gear mechanism.

  Wheels 22 are fixed to both ends of the wheel shaft 20 respectively. A wheel speed sensor 24 that generates a signal corresponding to the rotational speed of the wheel 22 is disposed in the vicinity of the wheel 22.

  MG 14 and motor 16 are each connected to inverter 26 via an AC power line. A boost converter 28 is connected to the inverter 26 via a DC power line. Further, a hybrid vehicle (HV) battery 30 is connected to the boost converter 28. The MG 14 and the motor 16 can exchange electric power with the HV battery 30 via the inverter 26 and the boost converter 28, respectively.

  The system of the present embodiment includes an ECU (Electric Control Unit) 40. The ECU 40 is connected to the MG 14, the motor 16, the inverter 26, the boost converter 28, and the HV battery 30 through signal lines. The ECU 40 determines the amount of charge SOC of the HV battery 30, the amount of power generated when the MG 14 and the motor 16 are driven by the internal combustion engine 10 based on the information acquired from these signal lines, and the MG 14 and the motor 16 are on the wheel 22 side. It is possible to detect the amount of regeneration that is generated by being driven from.

  The ECU 40 is further connected to a wheel speed sensor 24, an accelerator opening sensor 42, a navigation device 43, and the like. The ECU 40 can detect the vehicle speed SPD based on the output of the wheel speed sensor 24, and how the accelerator pedal is operated by the vehicle driver based on the output of the accelerator opening sensor 42. Can be detected. The ECU 40 can detect the traveling environment of the vehicle, for example, city / high-speed information, curve information, slope information, traffic jam information, and the like based on information from the navigation device 43.

  FIG. 2 is a diagram for explaining the power transmission path shown in FIG. 1 in detail. In FIG. 2, a region surrounded by a one-dot chain line indicates the power distribution mechanism 12. The power distribution mechanism 12 includes a ring gear 44. Two pinion gears 46 are arranged inside the ring gear 44. In addition, a sun gear 48 is disposed in the center of the ring gear 44 so as to be sandwiched between the pinion gears 46.

  A sun gear shaft 50 is fixed to the sun gear 48. The sun gear shaft 50 is also fixed to the rotor 52 of the MG 14. That is, in the configuration of FIG. 2, the rotor 52 and the sun gear 48 are integrated. Around the rotor 52, a stator 54 of the MG 14 is disposed. The rotor 52 can rotate inside the stator 54.

  The rotor 52 of the MG 14 and the sun gear shaft 50 have a hollow structure having a through hole at the center thereof. A crankshaft 56 of the internal combustion engine 10 is rotatably held in the hollow portion. For this reason, the crankshaft 56, the rotor 52, and the sun gear 48 can rotate relatively.

  All the rotation shafts of the pinion gears 46 are connected to the crankshaft 56. Therefore, when the crankshaft 56 rotates with respect to the sun gear 48, the pinion gear 46 revolves around the sun gear 48 together with the crankshaft 56.

  In FIG. 2, the motor 16 is shown on the leftmost side. The motor 16 includes a stator 58. A rotor 60 is rotatably disposed inside the stator 58. A ring gear shaft 62 is fixed at the center of the rotor 60. The ring gear shaft 62 has a hollow structure, and a crank shaft 56 is rotatably held therein. For this reason, the rotor 60 and the crankshaft 56 can rotate relatively.

  On the other hand, the ring gear shaft 62 fixed to the rotor 60 is also connected to the ring gear 44. That is, in the system of the present embodiment, the rotor 60 of the motor 16 is integrated with the ring gear 44. For this reason, when the rotor 60 and the crankshaft 56 are relatively rotated, the relative rotation is transmitted between the ring gear 44 and the pinion gear 46.

  In FIG. 2, a power take-out gear 64 of the speed reducer 18 is disposed between the power distribution mechanism 12 and the MG 14. The power take-out gear 64 is rotatably supported around the sun gear shaft 50 while being connected to the ring gear 44. Therefore, the power take-off gear 64 can rotate with respect to the sun gear shaft 50 and the crankshaft 56 integrally with the rotor 60 and the ring gear 44 of the motor 16.

  A power transmission gear 68 is connected to the power take-out gear 64 via a chain 66. The power transmission gear 68 is connected to the wheel shaft 20 shown in FIG. A speed change mechanism (not shown) is interposed between the power transmission gear 68 and the wheel shaft 20, but for the sake of convenience, the following description will be given assuming that the gear ratio of the speed change mechanism is constant.

As described above, the system shown in FIG. 2 includes the following three rotating systems.
First rotation system: system including crankshaft 56 and pinion gear 46 Second rotation system: system including rotor 52 of MG 14 and sun gear 48 Third rotation system: rotor 60 of motor 16, ring gear 44, and reduction gear 18 ( System including wheels 22)

  The three rotation systems described above are connected to each other in the power distribution mechanism 12. That is, the pinion gear 46 of the first rotating system and the sun gear 48 of the second rotating system have gear blades on their outer peripheral surfaces, and mesh with each other. The ring gear 44 of the third rotating system has a gear blade on the inner peripheral surface and meshes with the pinion gear 46. The three rotation systems described above can rotate relatively while being constrained by their gears.

[EV mode and HV mode]
Next, an electric vehicle mode (EV mode) and a hybrid vehicle mode (HV mode) realized by the system of the present embodiment will be described with reference to FIG. Here, the “EV mode” refers to a mode in which driving torque is generated only by electric power while combustion in the internal combustion engine 10 is stopped. The “HV mode” refers to all travel modes in which the internal combustion engine 10 generates torque.

  FIG. 3 is a diagram for explaining the relationship between the rotational speeds of the three rotary systems described above. Two straight lines 70 and 72 indicated by solid lines in FIG. 3 respectively illustrate the relationship between the rotational speeds established under the EV mode. Moreover, the straight line 74 shown with the broken line in FIG. 3 has illustrated the relationship of the rotation speed established under HV mode.

  In FIG. 3, the left vertical axis indicates the rotation speed of the second rotation system, that is, the rotation speed of the MG 14. The central axis indicates the rotation speed of the first rotation system, that is, the engine rotation speed. The right vertical axis indicates the number of rotations of the third rotation system, that is, the motor 16 and the wheels 22. In addition, here, a region above the reference line indicated by “0” is a forward rotation region, and a region below the reference line is a reverse rotation region.

  In the configuration described with reference to FIG. 2, the rotation shaft of the pinion gear 46 is connected to the crankshaft 56. For this reason, if the engine speed is 0, the center position of the pinion gear 46 is stationary. In this case, between the sun gear 48 and the ring gear 44, the rotation is inverted and transmitted, and the rotation number is transmitted proportionally.

  In other words, in the system of the present embodiment, as indicated by the solid lines 70 and 72 in FIG. 3, if the rotational speed of the MG 14 is appropriately controlled, the motor 16 and the wheels 22 are maintained while maintaining the engine rotational speed at “0”. The number of rotations can be appropriately changed to a desired value. That is, in the system according to the present embodiment, the relationship between the rotational speed of the MG 14 and the rotational speed of the motor 16 is controlled so that the engine rotational speed becomes “0”, so that the internal combustion engine 10 is stopped. The EV mode can be realized.

  In a scene where a large torque is required, such as during acceleration, the traveling mode of the vehicle is switched from the EV mode to a mode in which the internal combustion engine 10 generates torque, that is, the HV mode. As indicated by a broken line 74 in FIG. 3, in the HV mode, the engine speed is raised to the target speed. In this case, the pinion gear 46 revolves around the sun gear 48 at the target rotational speed, and further balances the rotational speed of the MG 14 and the rotational speed of the wheel 22 while rotating. At this time, for example, if torque is generated in the internal combustion engine 10 and the motor 16 and the MG 14 is rotated, the HV battery 30 can be charged by the MG 14 while securing the running torque. Further, if a torque is also generated in the MG 14, a larger running torque can be obtained. The system according to the present embodiment can appropriately switch the state in accordance with various demands in the vehicle.

[Rotating internal combustion engine]
FIG. 4 is a diagram for explaining the relationship between the rotational speeds realized by rotating the internal combustion engine 10 under the EV mode. The solid lines 76 and 78 shown in FIG. 4 indicate the relationship realized when the MG 14 and the motor 16 are controlled at the illustrated rotational speeds, respectively, with the combustion in the internal combustion engine 10 stopped. Yes.

  For example, in the relationship of the solid line 78, the MG 14 and the motor 16 are rotating in the forward rotation direction at substantially the same speed NE1. In this case, in the system of the present embodiment, the sun gear 48 and the ring gear 44 also rotate forward at substantially the same speed NE1. At this time, the pinion gear 46 revolves in the forward rotation direction at the rotational speed NE1 with almost no rotation. As a result, the crankshaft 56 connected to the pinion gear 46 rotates at the rotational speed NE1.

  Thus, in the system of the present embodiment, by appropriately controlling the rotational speed of the MG 14 and the rotational speed of the motor 16, the internal combustion engine 10 is caused to rotate while the combustion of the internal combustion engine 10 is stopped. Can do. That is, in the system of the present embodiment, it is possible to realize an EV mode with accompanying rotation of the internal combustion engine 10.

  When the internal combustion engine 10 is rotated in the EV mode, the engine speed can reach the target speed more quickly after switching to the HV mode than when the internal combustion engine 10 is stopped. Can do. Further, when the internal combustion engine 10 is rotated in the EV mode, noise and vibration associated with switching to the HV mode can be suppressed as compared with the case where the internal combustion engine 10 is stopped. For this reason, in order to improve the characteristics at the time of switching from the EV mode to the HV mode, it is desirable to cause the internal combustion engine 10 to rotate under the EV mode.

  However, the accompanying rotation of the internal combustion engine 10 involves a loss due to friction. For this reason, in the EV mode in which the internal combustion engine 10 is rotated, more electric power is required for the loss than in the EV mode in which the internal combustion engine 10 is stopped. On the other hand, in an environment in which the EV mode is frequently used in a hybrid vehicle, it is desirable that there is no power margin and that power consumption be suppressed as much as possible. In such an environment, since the frequency of switching to the HV mode is low, improvement in characteristics at the time of mode switching is not so important.

  Therefore, the system according to the present embodiment determines whether or not there is a margin in electric power, and if the determination is affirmed, the internal combustion engine 10 is rotated while the EV mode is being executed, When it is determined that there is no room, the EV mode is executed with the internal combustion engine 10 stopped.

[Driving pattern and power environment]
FIGS. 5A to 5F are diagrams for explaining the relationship between the traveling pattern of the hybrid vehicle and the power environment on the vehicle. Specifically, FIG. 5A shows a temporal change in the vehicle speed SPD. Here, an example is shown in which the vehicle travels at a low speed from time t1 to t2, and then travels at a high speed until time t3, and after time t3, the vehicle reaches a stop state at time t4.

  As shown in FIG. 5B, during the low-speed traveling of the vehicle (time t1 to t2) and during deceleration (time t3 to t4), the EV mode is selected because large torque is unnecessary. On the other hand, during acceleration to a high speed region and during high speed travel (time t2 to t3), the HV mode is adopted to obtain a large torque.

  The system of this embodiment collects deceleration energy by the MG 14 when the vehicle is decelerated (the energy may be collected by the motor 16 instead of or together with the MG 14). FIG. 5C shows a state in which the MG 14 generates regenerative power from time t3 to time t4. The regenerative power generated in this way is sent to the HV battery 30 and charged.

  In the HV mode in which the internal combustion engine 10 operates, the system according to the present embodiment causes the MG 14 to function as a generator if necessary (the power may be generated by the motor 16 instead of or together with the MG 14). ). FIG. 5D shows a state where the MG 14 receives power from the internal combustion engine 10 and generates power from time t2 to time t3. The electric power generated in this way is sent to the HV battery 30 and charged.

  FIG. 5E shows a temporal change in electric power consumed as the vehicle travels. While the vehicle is traveling in the EV mode, power is supplied to at least one of the MG 14 and the motor 16. Even in the HV mode, when output torque is required for the MG 14 and the motor 16, power is consumed in them. FIG. 5E shows an example in which the power consumption slightly increases after switching from the EV mode to the HV mode.

  FIG. 5F shows a temporal change in the charge amount SOC of the HV battery 30. In the system of this embodiment, the power of the HV battery 30 is consumed by the MG 14 and the motor 16 in accordance with the running state of the vehicle (see FIG. 5E). On the other hand, the HV battery 30 is charged with electric power generated by the MG 14 or the motor 16 (see FIGS. 5C and 5D). The charge amount SOC of the HV battery 30 indicates an increase / decrease according to their balance. Here, the SOC decreases during traveling in the EV mode (time t1 to t2), the SOC increases due to the positive balance in the HV mode (time t2 to t3), and during deceleration (time) The state in which the SOC increases with the regenerative power from t3 to t4) is illustrated.

  FIG. 6 shows an example of a change in the charge amount SOC over a predetermined period (t minutes). The long-term change tendency of the SOC changes according to the execution ratio of the EV mode and the HV mode, the power consumption by the air conditioner or the like, that is, the driving condition of the vehicle that determines the power balance. Under circumstances where the absolute amount of SOC is small, there is a high need to reduce power consumption in the first place, so it is appropriate not to rotate the internal combustion engine 10. In addition, in a situation where the SOC is greatly reduced, it is desirable to avoid further increase in power consumption regardless of the absolute amount of SOC. For this reason, in the present embodiment, the internal combustion engine 10 is rotated in the EV mode only when the SOC is sufficiently present and the decreasing tendency of the SOC is not unreasonably steep.

[Specific Processing in Embodiment 1]
FIG. 7 is a flowchart of a process executed by the ECU 40 to determine whether or not the internal combustion engine 10 is to be rotated during the EV mode. In the routine shown in FIG. 7, first, it is determined whether or not the charge amount SOC of the HV battery 30 is equal to or greater than a predetermined determination value (step 100). As described above, the ECU 40 can detect the SOC based on information supplied from the HV battery 30 or the like. Here, specifically, when the SOC is 60% or more of the maximum charge amount, it is determined that the SOC is the determination value or more.

  If it is determined in step 100 above that the SOC does not reach the determination value, it can be determined that it is necessary to reduce power consumption. In this case, processing for disconnecting the internal combustion engine 10 is performed in the EV mode (step 102). When this process is executed, the ECU 40 thereafter controls the relationship between the rotational speed of the MG 14 and the rotational speed of the motor 16 (wheel 22) so that the engine rotational speed becomes “0” in the EV mode (FIG. 3). As a result, the internal combustion engine 10 is stopped and power consumption in the EV mode is suppressed.

  On the other hand, if it is determined in step 100 that the SOC is equal to or greater than the determination value, it is then determined whether the SOC can be maintained at an appropriate level based on the regeneration amount and the power generation amount in the HV mode ( Step 104). More specifically, here, the reduction rate of the SOC average value for the past 1 minute (referred to as SOCAVt) with respect to the SOC average value for the previous one minute (referred to as SOCAVt-1) does not exceed the judgment value. How is it determined?

  When the decrease rate of SOCAVt does not exceed the determination value, it can be determined that the SOC can be maintained at an appropriate level even if the internal combustion engine 10 is rotated in the EV mode. For this reason, when the above determination is made, next, a process for rotating the internal combustion engine 10 in the EV mode is performed (step 106). When this process is executed, the ECU 40 thereafter controls the relationship between the rotational speed of the MG 14 and the rotational speed of the motor 16 (wheel 22) so that the engine rotational speed becomes “NE1” in the EV mode (see FIG. 4). As a result, a state suitable for switching to the HV mode is formed.

  If it is determined in step 104 above that the SOC cannot be maintained at an appropriate level with the current regeneration amount and power generation amount, then it is determined whether the electric power required to carry the internal combustion engine 10 is less than the determination value. (Step 108).

  Here, the ECU 40 first calculates the average power per unit time required for the rotation of the internal combustion engine based on the past operation history. The ECU 40 stores a map that defines the relationship between the operating state of the internal combustion engine 10 and the friction associated with rotation. The ECU 40 reads the friction at a certain timing from the map based on the past operation history (the friction is 0 if the internal combustion engine 10 is stopped). The read-out friction is multiplied by the engine speed at that timing and the sampling interval. The values calculated in this way are integrated over a past fixed period. The integrated value obtained as a result is normalized to a value per unit time, thereby calculating the electric power per unit time required for the rotation of the internal combustion engine 10. Thereafter, it is determined whether or not the calculated power is smaller than a determination value.

  If it is determined in step 108 that the electric power required for rotation is smaller than the determination value, it can be determined that the electric power environment does not deteriorate so much even if the internal combustion engine 10 is rotated in the EV mode. In this case, the ECU 40 gives priority to the characteristic improvement at the time of mode switching, and thereafter performs the processing of step 106.

  When traveling on an uphill with a continuous curve, the required torque decreases during the period of turning on the curve, and the EV mode is set. When the vehicle passes the curve, an acceleration request is generated and high load running in the HV mode is started. Such mode switching is repeatedly performed when climbing a mountain road. In this case, since high-load running is required as a whole, power consumption by the MG 14 and the motor 16 also increases, and the SOC tends to decrease. On the other hand, the execution time of the EV mode is short, and even if the internal combustion engine 10 is rotated, the power consumption due to the execution is not so much. On the other hand, under such circumstances, the improvement in responsiveness when switching from the EV mode to the HV mode significantly increases the drivability of the vehicle. According to the processing of step 108, even if the SOC is greatly reduced, if the power required for the rotation is small, it is possible to request the rotation. Therefore, the drivability in such a situation is effectively improved. be able to.

  When the vehicle is traveling on a flat road at a constant speed, the ratio of the EV mode is high, so the SOC is likely to be greatly reduced. In this case, since the ratio of the EV mode is high, the accompanying period of the internal combustion engine 10 becomes long, and the electric power required for the accompanying operation increases. On the other hand, since the frequency of switching to the HV mode is low, improving the characteristics at the time of switching is not a great merit. According to the processing in step 108, under such circumstances, it is possible to appropriately prohibit the accompanying and suppress unnecessary power consumption.

  As described above, according to the system of the present embodiment, even if the internal combustion engine 10 is rotated, the rotation is performed only in a situation where the power environment is not unduly deteriorated. For this reason, according to the system of the present embodiment, the situation in which the power environment of the vehicle is unduly deteriorated due to the rotation of the internal combustion engine 10 and the energy efficiency of the vehicle deteriorates as a result is effective. Can be avoided.

  In the first embodiment described above, whether to rotate the internal combustion engine 10 is switched according to whether the power environment of the vehicle is good or bad, but the present invention is limited to such switching. It is not a thing. That is, the electric power required for the rotation of the internal combustion engine 10 changes according to the rotation speed of the rotation. For this reason, in this invention, it is good also as adjusting the high and low of rotation speed with a rotation according to the quality of an electric power environment. Furthermore, it is good also as performing in combination with switching of execution / inhibition of a rotation, and the high / low adjustment of a rotation speed.

  In the first embodiment described above, a hybrid system using the three-shaft power distribution mechanism 12 is assumed. However, a system to which the present invention can be applied is not limited to such a system. Absent. For example, the present invention can be applied to a system in which a clutch mechanism is interposed between a crankshaft of an internal combustion engine and a rotating shaft of a motor. In this case, by switching connection / disconnection of the clutch, it is possible to switch between a state where the internal combustion engine is rotated and a state where the rotation is prohibited. Furthermore, the present invention can be applied to a system including a gear mechanism having a variable gear ratio between a crankshaft of an internal combustion engine and a rotating shaft of a motor. In this case, by changing the gear ratio of the gear mechanism according to whether the power environment of the vehicle is good or not, it is possible to realize the rotational speed according to the power environment. This also applies to the second embodiment described below.

  In Embodiment 1 described above, the determination regarding the SOC itself (step 100), the determination regarding the change tendency of the SOC (step 104), and the determination regarding the electric power required for carrying (step 106) are executed in combination. However, the present invention is not limited to this. That is, whether or not the internal combustion engine 10 is rotated, or the rotation speed of the internal combustion engine 10 may be determined based on at least one of these determinations. This also applies to the second embodiment described below.

  In the first embodiment described above, the ECU 40 controls the rotational speed of the MG 14 and the motor 16 in a state where the fuel supply to the internal combustion engine 10 is stopped, whereby the “EV realization means” in the first invention is provided. It has been realized. The ECU 40 controls the rotational speed of the MG 14 and the motor 16 while supplying fuel to the internal combustion engine 10, thereby realizing the “HV realization means” in the first invention. In addition, here, the mechanism shown in FIG. 2 corresponds to the “engine speed changing means” in the first invention, and the ECU 40 executes the processing of steps 100 and 104 in the first invention. “Charging state detection means” is realized. The ECU 40 performs the processing of steps 102 and 106 to realize the “revolving rotation speed control means” in the first invention.

  In the first embodiment described above, the gear mechanism having a variable gear ratio is disposed between the crankshaft 56 of the internal combustion engine 10 and the rotation shaft of the motor 16, thereby providing the “gear mechanism” according to the second aspect of the present invention. Can be realized. Furthermore, by interposing a clutch mechanism between the crankshaft 56 of the internal combustion engine 10 and the rotating shaft of the motor 16, the “clutch mechanism” in the third aspect of the invention can be realized.

  In the first embodiment described above, the “charge amount detection means” in the fourth aspect of the present invention is realized by the ECU 40 detecting the SOC. Then, the ECU 40 performs the processing of step 106 following step 100, thereby realizing the “revolving rotation speed control means” in the fourth aspect of the invention.

  Further, in the first embodiment described above, the “charge amount change tendency detecting means” in the fifth aspect of the present invention is realized by the ECU 40 executing the process of step 104. Then, the ECU 40 performs the processing of step 106 subsequent to step 104, thereby realizing the “revolving rotation speed control means” in the fifth aspect of the invention.

  In the first embodiment described above, the “accompanying power acquisition means” according to the sixth aspect of the present invention is implemented by the ECU 40 executing the process of step 108. Then, the ECU 40 performs the process of step 106 subsequent to step 108, thereby realizing the “revolving rotation speed control means” in the sixth aspect of the invention.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIG. The system of the present embodiment can be realized by causing the ECU 40 to execute the routine shown in FIG. 8 described below instead of the routine shown in FIG. 7 in the system of the first embodiment described above.

  The system of the first embodiment described above rotates the internal combustion engine 10 in the EV mode when the power environment in the vehicle has a margin. Incidentally, the purpose of rotating the internal combustion engine 10 in the EV mode is to improve drivability when switching to the HV mode. That is, even if the internal combustion engine 10 is rotated in the EV mode, no merit can be obtained unless switching to the HV mode occurs. In view of this, the system according to the present embodiment determines whether to rotate the internal combustion engine 10 in the EV mode in consideration of frequent switching from the EV mode to the HV mode.

[Specific Processing in Second Embodiment]
FIG. 8 is a flowchart of a routine executed by the ECU 40 in the present embodiment. In FIG. 8, steps that are the same as the steps shown in FIG. 7 are given the same reference numerals, and descriptions thereof are omitted.

  In the routine shown in FIG. 8, first, it is determined whether the switching frequency between the HV mode and the EV mode is equal to or higher than a predetermined determination value (step 110). Here, specifically, it is determined whether or not switching from the EV mode to the HV mode has been performed a number of times equal to or more than the determination value within the latest past period. As a result, if it is determined that the number of times of switching is equal to or greater than the determination value, it is determined that the internal combustion engine 10 is worth accompanying, and the process of step 106 is performed thereafter.

  On the other hand, if it is determined that the frequency of switching from the EV mode to the HV mode is low, it is then determined whether the ratio of the HV mode is equal to or greater than a predetermined value (step 112). When the ratio of the HV mode is equal to or greater than a predetermined value, it can be determined that there is a margin in the power generation environment. In this case, since the EV mode time is short, even if the internal combustion engine 10 is rotated in the EV mode, it can be determined that less power is required. In such an environment, it is desirable to keep the internal combustion engine 10 in preparation for switching to the HV mode in the EV mode even if the switching frequency is low. For this reason, if it is determined by the processing of step 112 that the ratio of the HV mode is equal to or greater than the predetermined value, the processing for rotation is performed in step 106 thereafter.

  On the other hand, if it is determined in step 112 that the ratio of the HV mode is low, the latest traveling pattern of the predetermined period in the past is not a pattern in which a great merit can be obtained by the rotation of the internal combustion engine 10, and Thus, it can be determined that the pattern requires a large amount of electric power to rotate the internal combustion engine 10 (because the EV mode period is long). In this case, the ECU 40 next predicts a subsequent traveling pattern and determines whether or not there is a follow-up based on the prediction result (step 114).

  In step 114, first, based on the information acquired from the navigation device 43, it is determined whether there is a possibility of frequent switching to the HV mode in the subsequent travel. For example, here, it is determined whether the current traveling road corresponds to any one of an urban area, a curve, a slope, and a traffic jam. When the current travel route corresponds to any one of them, it can be determined that there is a high possibility that acceleration / deceleration is repeated in the subsequent travel. Therefore, if the above determination is affirmed, the process of step 106 is then executed.

  In step 114, it is further determined whether overtaking is frequently performed based on the travel history of the vehicle. Whether or not the overtaking has been performed can be determined based on the vehicle speed SPD and the accelerator opening. When the frequency is high, it can be determined that there is a high possibility that overtaking will be performed in the subsequent travel. When overtaking, switching from the EV mode to the HV mode is likely to occur. For this reason, the ECU 40 performs the process of step 106 thereafter even when it is determined that the overtaking frequency is high.

  If it is determined in step 114 that the current travel route does not correspond to an urban area or the like and the overtaking frequency in the travel history is not high, switching from the EV mode to the HV mode is frequently performed in subsequent travel. Can be determined not to occur. In this case, since the merit of rotating the internal combustion engine 10 in the EV mode is small, the process of step 102 is subsequently executed.

  As described above, according to the system of the present embodiment, the scene where the internal combustion engine 10 is rotated in the EV mode can be limited to a scene where a sufficient effect is predicted. That is, according to the system of the present embodiment, it is possible to prohibit the internal combustion engine 10 from being rotated in a scene where sufficient merit cannot be obtained even if there is a margin in the power environment. For this reason, according to the system of the present embodiment, the energy efficiency of the vehicle can be further improved as compared with the case of the first embodiment.

  In the second embodiment described above, whether or not the internal combustion engine 10 is to be rotated is switched according to the frequency of switching to the HV mode, but the present invention is limited to such switching. It is not a thing. That is, it is good also as adjusting the high / low of rotation speed according to said switching frequency. Furthermore, it is good also as performing in combination with switching of execution / inhibition of a rotation, and the high / low adjustment of a rotation speed.

  In the second embodiment described above, a hybrid system using the three-shaft power distribution mechanism 12 is assumed. However, a system to which the present invention can be applied is not limited to such a system. Absent. For example, the present invention can be applied to a system in which a clutch mechanism is interposed between a crankshaft of an internal combustion engine and a rotating shaft of a motor. In this case, by switching connection / disconnection of the clutch, it is possible to switch between a state where the internal combustion engine is rotated and a state where the rotation is prohibited. Furthermore, the present invention can be applied to a system including a gear mechanism having a variable gear ratio between a crankshaft of an internal combustion engine and a rotating shaft of a motor. In this case, by changing the gear ratio of the gear mechanism according to whether the power environment of the vehicle is good or not, it is possible to realize the rotational speed according to the power environment.

  In Embodiment 1 described above, the determination regarding the SOC itself (step 100), the determination regarding the change tendency of the SOC (step 104), and the determination regarding the electric power required for carrying (step 106) are executed in combination. However, the present invention is not limited to this. That is, whether or not the internal combustion engine 10 is rotated, or the rotation speed of the internal combustion engine 10 may be determined based on at least one of these determinations.

  In the second embodiment described above, the “switching frequency detecting means” according to the seventh aspect of the present invention is realized by the ECU 40 executing the processing of step 110 described above. Further, the ECU 40 executes the process of step 106 subsequent to step 110, thereby realizing the “revolving rotation speed control means” in the seventh aspect of the invention.

  In the second embodiment described above, the “switching frequency predicting means” according to the ninth aspect of the present invention is implemented when the ECU 40 executes the process of step 114. Further, the ECU 40 performs steps 102 and 106 subsequent to steps 110 and 114, thereby realizing the “revolving rotation speed control means” in the ninth aspect of the invention.

It is a figure for demonstrating the structure of the hybrid vehicle of Embodiment 1 of this invention. It is a figure for demonstrating in detail the power transmission path | route shown in FIG. It is a figure for demonstrating the relationship of the rotation speed of the three rotation systems contained in the mechanism shown in FIG. It is a figure for demonstrating the relationship of the rotation speed implement | achieved by rotating the internal combustion engine 10 under EV mode. It is a figure for demonstrating the relationship between the driving | running | working pattern of a hybrid vehicle, and the electric power environment on a vehicle. It is a figure which shows the example of the change of charge amount SOC over a predetermined period (t minutes). It is a flowchart of the routine performed in Embodiment 1 of the present invention. It is a flowchart of the routine performed in Embodiment 2 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 12 Power distribution mechanism 14 Motor generator (MG)
16 Motor 18 Reducer 40 ECU (Electric Control Unit)
HV Hybrid vehicle EV Electric vehicle

Claims (10)

A control device for a hybrid vehicle comprising an internal combustion engine and a motor,
A battery capable of transferring power to and from the motor;
EV realizing means for realizing an electric vehicle mode in which a driving torque is generated in the motor in a state where fuel supply to the internal combustion engine is stopped;
HV realization means for realizing a hybrid vehicle mode for generating a driving torque in the internal combustion engine;
Engine speed changing means for changing the engine speed under the electric vehicle mode;
Charge state detection means for detecting the charge state of the battery;
Under the electric vehicle mode, the engine speed changing means for controlling the engine speed changing means based on the state of charge of the battery; and
A control apparatus for a hybrid vehicle, comprising: The engine speed varying means includes a gear mechanism with a variable gear ratio interposed between a crankshaft of the internal combustion engine and a rotating shaft of the motor,
2. The control apparatus for a hybrid vehicle according to claim 1, wherein the accompanying rotation speed control means controls the gear ratio based on a state of charge of the battery. The engine speed variable means includes a clutch mechanism interposed between a crankshaft of the internal combustion engine and a rotation shaft of the motor,
2. The control apparatus for a hybrid vehicle according to claim 1, wherein the follow-up rotation speed control means switches between a connected state and a non-connected state of the clutch mechanism based on a state of charge of the battery. The charge state detection means includes a charge amount detection means for detecting a charge amount of the battery,
When the charge amount is greater than or equal to a predetermined value, the accompanying rotation speed control means has a higher engine speed under the electric vehicle mode than when the charge amount is less than the predetermined value. The control apparatus for a hybrid vehicle according to claim 1, wherein the engine speed variable means is controlled as described above. The charge state detection means includes a charge amount change tendency detection means for detecting a change tendency of the charge amount of the battery,
The follow-up rotation speed control means is more effective in the electric vehicle mode when the change tendency of the charge amount is on the increase side than the determination criterion, compared with the case where the change tendency is on the decrease side with respect to the determination criterion. 5. The control apparatus for a hybrid vehicle according to claim 1, wherein the engine speed changing means is controlled so that the engine speed underneath becomes high. The accompanying power acquisition means for acquiring the accompanying power required to rotate the internal combustion engine at a desired rotational speed under the electric vehicle mode,
When the accompanying power is less than or equal to a predetermined value, the accompanying rotation speed control means has an engine speed under the electric vehicle mode as compared with a case where the accompanying power exceeds the predetermined value. 6. The control device for a hybrid vehicle according to claim 1, wherein the engine speed changing means is controlled so as to be high. A control device for a hybrid vehicle comprising an internal combustion engine and a motor,
EV realizing means for realizing an electric vehicle mode in which a driving torque is generated in the motor in a state where fuel supply to the internal combustion engine is stopped;
HV realization means for realizing a hybrid vehicle mode for generating a driving torque in the internal combustion engine;
Engine speed changing means for changing the engine speed under the electric vehicle mode;
Switching frequency detection means for detecting the switching frequency from the electric vehicle mode to the hybrid vehicle mode;
When the switching frequency is equal to or higher than a predetermined value, the engine speed variable means is configured so that the engine speed under the electric vehicle mode is higher than when the switching frequency is less than the predetermined value. A rotation speed control means for controlling
A control apparatus for a hybrid vehicle, comprising:   8. The hybrid vehicle control device according to claim 7, wherein the switching frequency detection means calculates the switching frequency based on a switching history from the electric vehicle mode to the hybrid vehicle mode in a past predetermined period. . Switching frequency prediction means for predicting switching frequency from the electric vehicle mode to the hybrid vehicle mode,
8. The control apparatus for a hybrid vehicle according to claim 7, wherein the accompanying rotation speed control means controls the engine speed variable means based on each of the detection result and prediction result of the switching frequency. A navigation device that acquires information about the driving environment of the vehicle;
The hybrid vehicle control device according to claim 9, wherein the switching frequency predicting unit predicts the switching frequency based on the traveling environment.

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