JP2018134942A - Control device of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To switch traveling modes according to an individuality of a driver by learning.SOLUTION: In the control device of a hybrid vehicle, traveling modes include: a discharge mode in which an engine 10 is stopped and a vehicle is allowed to travel by driving a motor generator MG2 by electric power from a battery 22; a charge mode in which the vehicle is allowed to travel while charging the battery 22 with electric power generated by a motor generator MG1 or regenerative electric power of the motor generator MG2; and a power mode in which the vehicle is allowed to travel by both of output of the engine 10 and output of the motor generator MG2. The control device has a map for determining which should be selected from between the discharge mode and the charge mode, which learns history of requested output and vehicle speed of the vehicle and renews the map on the basis of the learning result.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device for a hybrid vehicle that controls a travel mode in the hybrid vehicle.

  Hybrid vehicles equipped with a motor generator and an internal combustion engine (engine) are widely used. In this hybrid vehicle, there are a mode that uses a motor generator, a mode that uses only an engine, and a mode that uses both as driving force for driving the vehicle. In addition, as to charging of the power storage device, there are a mode of charging with power generated by driving the internal combustion engine and a mode of charging with regenerative power of the motor generator.

  Patent Document 1 discloses that in a hybrid vehicle equipped with two motors and an engine, a mode in which the engine travels, a mode in which the motor travels, and a mode in which the motor travels are switched.

  Japanese Patent Application Laid-Open No. 2004-228561 basically shows switching between a mode in which the vehicle travels without using the driving force of the engine and a mode in which the vehicle travels using the driving force of the engine as appropriate.

JP 2016-179727 A WO2000 / 125186A1 publication

  Here, as described above, there are various types of travel modes of the hybrid vehicle, but there are also various types of driving force transmission mechanisms, and various travel modes cannot always be selected. For example, in a series hybrid, it is not possible to select a travel mode based on engine driving force. Further, in a parallel hybrid that uses planetary gears for transmission, there are predetermined restrictions on the driving of the engine and the motor generator.

  If the series hybrid mode and the parallel hybrid mode can be freely switched and used, more efficient vehicle travel may be achieved. In addition, the choice of travel mode varies depending on the driver's driving characteristics. Therefore, it is considered necessary to consider the characteristics of the driver in order to effectively switch the driving mode.

  The present invention includes an internal combustion engine that outputs power, a chargeable / dischargeable power storage device, a generator that generates power using the power of the internal combustion engine and charges the power storage device, and is driven by power from the power storage device to output power. In addition, a hybrid vehicle control device that controls switching of a travel mode in a hybrid vehicle including a motor generator that generates regenerative electric power using the inertia force of the vehicle, the travel mode stops the internal combustion engine Driving the motor generator with electric power from the power storage device to drive the vehicle while discharging from the power storage device; and driving the vehicle while charging the power storage device with the generated power of the generator or the regenerative power of the motor generator And a third mode in which the vehicle is driven by both the output of the internal combustion engine and the output of the motor generator. The control device has a map for selecting either the first mode or the second mode according to the required output of the vehicle and the vehicle speed, learns the required output of the vehicle and the history of the vehicle speed, and based on the learning result Update the map.

  In addition, it is preferable to update the map so as to calculate the request output and the appearance frequency of the speed in the vehicle travel and reduce the deviation of the appearance frequency of the first mode and the second mode.

  Further, it is preferable to update the map so that the fuel consumption by the internal combustion engine is minimized when the required output and the appearance frequency of the speed in the vehicle travel are calculated and the same cruising distance is maintained.

  Further, the third mode may be selected with respect to the requested output, with the maximum output of the motor generator as a threshold value.

  Further, it is preferable to supplement the positive difference between the output of the maximum efficiency point of the internal combustion engine corresponding to the vehicle speed and the required output with the output of the motor generator.

  Further, it is preferable to absorb the negative difference between the output of the maximum efficiency point of the internal combustion engine corresponding to the vehicle speed and the required output by the power generation of the motor generator.

  According to the present invention, effective driving mode switching according to the characteristics of the driver can be performed by learning.

It is a figure which shows the basic composition of a hybrid vehicle. It is a figure which shows discharge mode. It is a figure which shows a power mode. It is a figure which shows charge mode (1). It is a figure which shows charge mode (2). It is a flowchart of a mode switching process. It is a figure which shows a mode switching map. It is a figure explaining an argument and an evaluation function.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described herein.

"Basic structure"
FIG. 1 shows a basic structure of a hybrid vehicle according to the embodiment.

  An output shaft of the engine 10 that is an internal combustion engine is connected to the transmission 12. The transmission 12 is a simple two-stage transmission, and can switch between two fixed speed ratios of low and high. The output shaft of the transmission 12 is connected to the axle 16 via the clutch 14. The axle 16 is connected to the wheel 20 via a differential gear 18. Therefore, the wheel 20 can be rotated and driven by the output of the engine 10, and the gear ratio can be switched in two steps by the transmission 12.

  Further, a gear provided on the output shaft of the engine 10 is provided so as to be able to mesh with a gear provided on the rotation shaft of the generator MG1, and the generator MG1 can be driven by the output of the engine 10. The power generation output of the generator MG1 is supplied to a battery 22 as a chargeable / dischargeable power storage device. The output of the generator MG1 is converted into DC power by the power converter and supplied to the battery 22.

  A motor generator MG2 is connected to the battery 22, and the motor generator MG2 can be driven by the electric power of the battery 22. The gear provided on the output shaft of motor generator MG2 can mesh with the gear provided on axle 16 and axle 16 can be rotated by the output of motor generator MG2. In addition, by driving motor generator MG2 by rotation of wheel 20, electric power can be regenerated by motor generator MG2, and battery 22 can be charged by regenerative electric power. A power converter is also provided between motor generator MG2 and battery 22, and performs DC / AC conversion.

  With such a configuration, the vehicle can be driven by the driving force of the engine 10 or the motor generator MG2, or both, and the battery 22 can be charged by the output of the engine 10. Therefore, the series mode and the parallel mode can be completely made independent.

  A control device 24 is provided, and receives various kinds of information and controls the engine 10, the generator MG1, the motor generator MG2, the transmission 12, and the clutch 14.

"action mode"
2 to 5 show images of various operation modes. In each figure, “drive state: drive” is indicated by a thick line, “driven state: driven” is indicated by a thin line, and “non-drive state: free” is indicated by a broken line.

  FIG. 2 shows a discharge mode that is the first mode. In the discharge mode, the engine 10 is disconnected by the clutch 14. Motor generator MG2 is driven by the electric power from battery 22, and the vehicle travels by the driving force of motor generator MG2. Since the engine 10 is not driven, the battery 22 is discharged and the vehicle travels using this as power.

  FIG. 3 shows a power mode that is the third mode. In the power mode, the clutch 14 is engaged, the power of the engine 10 is transmitted to the wheels 20, the motor generator MG <b> 2 is driven by the power of the battery 22, and the driving force of the motor generator MG <b> 2 is transmitted to the wheels 20. 10 and the motor generator MG2 drive the vehicle in parallel.

  In this mode, if possible, control may be performed so that the difference between the output of the highest efficiency point of engine 10 corresponding to the vehicle speed and the required output is supplemented by motor generator MG2. Although not shown, when the output of the maximum efficiency point of the engine 10 corresponding to the vehicle speed exceeds the required output, the difference may be absorbed by the power generation of the generator MG1.

  3A shows a high gear ratio mode in which a high gear is selected by the transmission 12, and FIG. 3B shows a low gear ratio mode in which a low gear is selected by the transmission 12.

  4 and 5 show the charging mode which is the second mode. In the charging mode, the battery 22 is charged with electric power from the generator MG1 or the motor generator MG2.

  4 (a) and 4 (b), the engine 10 is driven to engage the clutch 14, and an output corresponding to the requested output is driven by the driving force of the engine 10. Then, power is generated by the generator MG <b> 1 using the surplus with respect to the requested output, and the battery 22 is charged. The engine 10 is basically driven at the highest efficiency point. That is, the generator MG1 is driven with a positive difference between the output of the highest efficiency point of the engine 10 corresponding to the vehicle speed and the required output.

  4A shows the low gear parallel mode in which the low gear is selected in the transmission 12, and FIG. 4B shows the high gear parallel mode in which the high gear is selected in the transmission 12.

  FIG. 5A shows the series mode. In this mode, the clutch 14 is disconnected, the generator MG1 is driven by the engine 10, and the battery 22 is charged by the generated power of the generator MG1. Further, motor generator MG2 is driven by the electric power of battery 22, and the vehicle is driven by the driving force of motor generator MG2. That is, in the series mode, the driving force of engine 10 is used only for power generation, and the vehicle travels with the driving force of motor generator MG2. In this case as well, the engine 10 is basically driven at the highest efficiency point.

  FIG. 5B shows the regeneration mode. In this mode, electric power is generated by the motor generator MG2 using the inertial force of the vehicle. That is, the axle 16 is rotated by the rotation of the wheel 20 by the inertial force of the vehicle, thereby generating electric power by the motor generator MG2, and charging the battery 22 by the generated electric power. That is, regenerative electric power is generated by regenerative braking of the vehicle, and the generated electric power is supplied to the battery 22.

  When the power generation capacity of the generator MG1 is small, the series mode in FIG. 4A may be a discharge mode, and such a mode may be included.

"Control logic"
FIG. 6 shows a flow for switching control between three modes of charge / discharge / power.

  First, the required output of the vehicle is calculated from the driver's accelerator operation state, etc., and it is determined whether the calculated output request is positive (S11). If the determination is No, the vehicle is in a decelerating state and regenerative braking is possible. Therefore, the charging mode is entered (S12), and the engine 10 is stopped (S13). Then, the motor generator MG2 performs regenerative braking according to the required output (S14). That is, as shown in FIG. 4B, excess inertia energy in the vehicle or the motor generator MG2 collects / generates power, and the battery 22 is charged.

  In S11, in the case of Yes, it is determined whether the output is equal to or less than the requested output and the output possible threshold value of motor generator MG2 (S15). The output possible threshold value corresponds to the maximum output of motor generator MG2 (usually the rated maximum output may be changed depending on the situation such as the temperature of MG2, etc.). The output of the motor generator MG2 alone cannot meet the required output. Therefore, if the determination in S15 is No, the power mode is entered (S16), and the engine 10 is driven (S17). Then, as shown in FIGS. 5A and 5B, both the driving force of the engine 10 and the driving force of the motor generator MG2 are transmitted to the axle 16 to travel in the parallel mode (S18).

  If the determination in S15 is Yes, the required output can be supplemented by the single output of the motor generator MG2. In this case, various modes can be selected. Therefore, efficient selection is performed according to the map stored in the control device 24.

  In consideration of the required output and the vehicle speed, the discharge mode is efficient, and when this is selected, the mode shifts to the discharge mode (S20). Then, the engine 10 is stopped (S21), and as shown in FIG. 2, EV traveling is performed only with the output of the motor generator MG2 (S22).

  If it is No in S19, it is determined that the charging mode is efficient. Therefore, the charging mode is entered (S23), and the engine 10 is driven (S24). Next, it is determined which one of the series mode and the parallel mode is efficient from the required output, the vehicle speed, and the like (S25).

  If it is determined in S25 that the series mode is efficient, the vehicle travels in the series mode shown in FIG. 4A (S26). If it is determined in S25 that the parallel mode is efficient, the vehicle travels in the series mode shown in FIGS. 3A and 3B (S27).

  In the power mode and parallel mode, either low gear or high gear may be selected according to the required output and the vehicle speed.

“Discharging / charging selection in S19”
In S19, the control device 24 determines which one of the discharge mode and the charge mode is efficient. In particular, driver characteristics are taken into account in this determination.

  For example, by predicting the driving tendency from the input data of the driver, it is possible to perform mode determination that eliminates the bias of the charge / discharge frequency in accordance with the driver's tendency.

  First, as a default setting, a map for preferentially selecting the higher one of the discharge mode and the charge mode is prepared. For example, a map as shown in FIG. 7A is prepared, and the discharge mode and the charge mode are selected from the required output and the vehicle speed. The power mode determined by the determination in S15 is shown in FIG.

  This default map maximizes the efficiency of driving or charging / discharging alone at any operating point.

  However, there is a possibility that the vehicle speed and the accelerator opening may be biased depending on the use environment and the user. For example, in the case of a user who uses in a mountain area, the low frequency and high torque area is frequently used because of climbing. When the default map is applied to such a user, the selected mode is also biased, and there is a possibility of causing excessive charging and excessive discharging.

  For example, as shown in FIG. 7C, when the frequency distributions are compared, the charging mode increases and there is a possibility of overcharging. In addition, the contour line shown with a broken line in Fig.7 (a) (b) has shown frequency, and has shown that frequency is so high that it is an inner island.

  In this way, when the mode is switched using the default map, drivability and efficiency deterioration due to loss of excessive charge or travel mode limitation when power is insufficient is assumed depending on the usage environment and driver characteristics. Is done.

  Therefore, the mode switching map is learned according to the learning result by learning the usage frequency distribution of the operating area from the driving history of the driver. That is, updating is performed sequentially with the objective function of minimizing the difference in charge / discharge amount and maximizing operation efficiency. As a result, the map is updated so that the charge / discharge balance and the efficiency are compatible with the driving tendency of the driver.

  Further, it is preferable to update the map so that the fuel consumption by the internal combustion engine is minimized when the required output and the appearance frequency of the speed in the vehicle travel are detected and the same cruising distance is maintained. That is, the map can be updated so that the frequency of use of the discharge mode increases.

  When there are many climbs like the driver | operator (user) of FIG. 7, as shown in FIG.7 (b), a low speed high torque area is changed from charge to discharge, and the selection frequency of a mode is equalized.

  As shown in FIG. 7 (d), the bias in the selected mode is reduced to reduce running restrictions and losses due to excessive charge / discharge, as shown in FIG. 7 (d). It can be avoided.

  Here, FIG. 8 shows argument candidates as learning items, an evaluation function that receives an argument, and expected effects.

  Factor candidates include “accelerator opening”, “vehicle speed”, “position”, “route information”, etc. as required output prediction data, and “SOC”, “temperature”, “age (used) as vehicle status data. Year)). The evaluation functions include “loads such as engine, motor generator, battery”, “fuel consumption”, “energy consumption”, “response speed (ensure output margin)”, “running sound”, “torque fluctuation” The vehicle life, fuel consumption, cruising range, drivability, silence, ease of getting sick, etc. can be evaluated.

  For example, by learning the loads of the engine 10, the generator MG1, and the motor generator MG2, the respective lifetimes can be estimated and evaluated. Therefore, by changing the mode switching such as the discharge mode, the charging mode, the parallel mode, and the series, it is possible to change the driving mode switching threshold value so that there is no difference in the life of each device. Further, if the charging mode and the discharging mode are frequently switched, the life of the battery 22 is shortened. Therefore, depending on the characteristics of the driver, if the number of switching between the charging mode and discharging mode increases in the default map, the map may be changed or other conditions (for example, hysteresis related to switching) may be reduced. Can be improved.

  Further, when the fuel consumption is large (fuel efficiency is poor), the range of the discharge mode can be expanded to reduce the frequency of engine driving. Furthermore, from the relationship between the accelerator opening and the vehicle speed (acceleration), when the response speed is not sufficient, the switching to the power mode can be performed early (relatively low vehicle speed, required output). Further, when the driving frequency of the engine 10 is high, the running noise can be reduced by increasing the frequency of the discharge mode. For example, when the battery 22 can be charged from an external power source (including a household power source), fuel consumption can be improved by frequently using the discharge mode. For this reason, the distance of one trip can be learned and the discharge mode can be used frequently. The cruising range priority, fuel efficiency priority, etc. may be selectable. In the series mode, the engine 10 can be operated with maximum efficiency. Therefore, it is preferable to change the switching condition so that the frequency of traveling in the series mode is increased.

  Further, from the past history, when the torque fluctuation during traveling is large, it is preferable to make a change such as reducing (decreasing) the change in the required output with respect to the change in the accelerator opening so as to reduce this.

  Furthermore, various modes may be prepared for driving characteristics so that the driving characteristics can be selected according to the driver's preference. Then, the evaluation function for each mode can be learned at the time of driving by the driver, and a driving mode suitable for each driver can be realized.

  For example, a car sickness reduction function is prepared, and a driver who travels a lot on a mountain road uses the car sickness reduction function. As a result, the learning function of the machine learning evaluation function, the acceleration during acceleration / deceleration, the lateral G, etc. are learned by the driver's accelerator and steering input, and the driving method is selected to limit the demand output. It becomes possible to do.

  In this way, by selecting the learning input argument and the evaluation function as shown in FIG. 8, it is possible to give a characteristic tailored to the driver's preference.

  Furthermore, in this embodiment, the transmission 12 is provided, and when the vehicle is driven by the engine 10, the gear ratio can be automatically optimized.

"Effect of the embodiment"
By performing machine learning on the driver's input information and performing required output prediction, it is possible to search for mode selection that minimizes energy consumption, and to prevent efficiency reduction during charging and discharging. In addition, by applying machine learning to the driver's input information and reflecting the frequency deviation of the used operation area in the map, it is possible to alleviate the deviation of the number of charge / discharge times and avoid excessive charge / discharge.

  As a result, the fuel consumption of the internal combustion engine due to the deviation between the drivers can be minimized, and the deviation in fuel consumption and cruising distance can be suppressed.

10 engine, 12 transmission, 14 clutch, 16 axle, 18 differential gear, 20 wheel, 22 battery, 24 control device, MG1 generator, MG2 motor generator.

Claims (6)

An internal combustion engine that outputs power;
A chargeable / dischargeable power storage device;
A generator that generates power by the power of the internal combustion engine and charges the power storage device;
A motor generator that is driven by electric power from the power storage device and outputs motive power, and generates regenerative power using the inertial force of the vehicle;
A hybrid vehicle control device for switching and controlling a driving mode in a hybrid vehicle including:
The driving mode is
A first mode in which the internal combustion engine is stopped, the motor generator is driven with electric power from the power storage device, and the vehicle is driven while discharging from the power storage device;
A second mode in which the vehicle travels while charging the power storage device with the generated power of the generator or the regenerative power of the motor generator;
A third mode in which the vehicle is driven by both the output of the internal combustion engine and the output of the motor generator;
Including
The control device
According to the required output of the vehicle and the vehicle speed, it has a map as to which of the first mode and the second mode is selected,
Learn the vehicle's required output and vehicle speed history, and update the map based on the learning results.
Control device for hybrid vehicle. The hybrid vehicle control device according to claim 1,
Update the map so as to calculate the frequency of appearance of the required output and speed in vehicle travel and reduce the bias in the appearance frequency of the first mode and the second mode.
Control device for hybrid vehicle. The hybrid vehicle control device according to claim 1,
Update the map so that the fuel consumption by the internal combustion engine is minimized when the required output and the appearance frequency of the speed in vehicle travel are calculated and the same cruising distance is maintained.
Control device for hybrid vehicle. A control device for a hybrid vehicle according to any one of claims 1 to 3,
Select the third mode with the maximum output of the motor generator as a threshold for the required output.
Control device for hybrid vehicle. A control device for a hybrid vehicle according to any one of claims 1 to 4,
Supplement the positive difference between the output of the highest efficiency point of the internal combustion engine according to the vehicle speed and the required output with the output of the motor generator,
Control device for hybrid vehicle. A control device for a hybrid vehicle according to any one of claims 1 to 5,
Absorb the negative difference between the output of the highest efficiency point of the internal combustion engine according to the vehicle speed and the required output with the power generation of the motor generator,
Control device for hybrid vehicle.