JP2005170143A - Drive control device for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To satisfy a power generation demand without giving a sense of incongruity by gradually lowering a driving force of a vehicle and urging a driver to carry out shift down, when the power generation demand is generated during traveling. <P>SOLUTION: The drive control device for a hybrid vehicle comprises an engine 11, a stepped transmission 12, and a motor generator 13. When the charging state of a battery 15 is lowered and charging is required, the motor generator 13 is made to carry out initial power generating operation. When a driving power increasing demand of a driver is outputted in this state, a shift stage of the stepped transmission 12 is shifted to a lower state side, and the power generating torque of the motor generator 13 is increased to a power generation amount correspondent to a charging demand of the battery 15. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an improvement in a drive control device for a hybrid vehicle.

  2. Description of the Related Art As a vehicle drive device, a parallel hybrid drive device is known that is configured to combine an engine and a motor generator and transmit both the output of the engine and the motor generator to a drive shaft. It is also known to use a stepped transmission with high transmission efficiency as a transmission for transmitting engine output to a drive shaft.

  If there is a power generation request from the battery while the vehicle is running by the engine, a part of the engine output is consumed as the power generated by the motor generator. In this case, in order to satisfy the driver's required driving force while generating power, it is necessary to increase the output of the engine by the power generation output, and it is necessary to increase the rotational speed of the engine depending on the amount of power generation. When the stepped transmission is provided as described above, it is necessary to increase the rotational speed of the engine and switch the shift step of the stepped transmission to the low speed step. When the gear stage of the stepped transmission is automatically switched to the low speed stage in this way, the driver feels uncomfortable due to an unexpected shift shock.

Therefore, even if there is such a power generation request, the stepped transmission changes the normal shift map of the stepped transmission to a power generation priority shift map only if the current gear stage can be maintained. However, this is disclosed in Patent Document 1.
JP 2003-130199 A

  However, when the surplus torque sufficient for the engine output is small, if the same shift speed is maintained, the power generation request cannot be sufficiently answered, and the battery cannot be charged quickly. On the other hand, if the stepped transmission is shifted down, the marginal driving force can be increased. However, if the driver is shifted down without increasing the driving force requirement, the driver feels uncomfortable.

  In order to solve such a problem, the present invention reduces the driving force of the vehicle little by little when a power generation request is made during driving, thereby prompting the driver to shift down without causing a sense of incongruity. The purpose is to secure power generation torque.

A drive control apparatus for a hybrid vehicle of the present invention includes an engine, a stepped transmission connected to the engine, a motor generator that regenerates part of the output of the engine, and generates power.
In a hybrid vehicle drive control device comprising a battery that stores regenerative power of the motor generator, a normal shift map for selecting a gear position of a stepped transmission based on a driver's driving force request, and a driving force of the driver A power generation priority shift map for selecting a shift speed of the stepped transmission based on the request and the power generation amount of the motor motor generator, and the charge state of the battery is reduced during traveling with reference to the normal shift map. When the need for charging arises, the motor generator is caused to perform an initial power generation operation, and when a driving force increase request is output from the driver, the stepped transmission is set to a low speed stage with reference to the power generation priority shift map. And the initial power generation operation is changed to a power generation operation corresponding to the charging request of the battery to cause the motor generator to perform a power generation operation.

  According to the present invention, when the battery charge state decreases during traveling and the charging needs to be performed, the motor generator is caused to generate power during the initial power generation operation. The power is relatively reduced and the vehicle speed is also gradually reduced. For this reason, the driver depresses the accelerator pedal to detect this and increase the driving force. When a request to increase the driving force is output in this way, the gear stage of the stepped transmission is switched to the low speed stage side, and the output torque increases, so the motor generator is operated with the power generation torque according to the battery demand. As a result, the battery can be charged stably and quickly without causing the driver to feel uncomfortable due to an unexpected shift.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

1 and 2 show a drive system for a hybrid vehicle to which the present invention is applied.
In FIG. 1, reference numeral 11 denotes an engine, which employs a gasoline engine, a diesel engine, or the like, and the driving force of the engine 11 is transmitted to the transmission 12. The transmission 12 is a stepped transmission, and has a plurality of gear stages (shift stages), and generally includes an automatic transmission (hereinafter referred to as MT) using a planetary gear and a spur gear group and is manually operated. An automatic mechanical transmission (hereinafter referred to as AMT) in which only the speed change operation of the transmission is automated is used, and a 6-speed AMT is illustrated here.

  A motor generator (hereinafter referred to as MG) 13 is connected to the output side of the transmission 12, and the MG 13 generates electric power during traveling at a reduced speed or generates a driving force upon receiving electric power. The driving force of the engine 11 and the MG 13 is transmitted from the output shaft 16 to the left and right driving wheels 18 via the differential gear 17. In FIG. 1, the MG 13 is disposed on the output side of the transmission 12. However, the MG 13 may be disposed as long as the engine 11 can generate power with the MG 13 while the vehicle 11 is transmitting the vehicle driving force.

  Note that FIG. 3 shows the shift stages of the transmission 12 when the vehicle is driven only by the output of the engine 11 (shown by a solid line) and when driven by the output of the engine 11 and the MG 13 (shown by a dotted line). The relationship between the corresponding driving force and vehicle speed is shown. When the driving force of the MG 13 is applied to the engine 11, the driving force of the vehicle increases accordingly.

  A control device 14 is provided to control the operation of the MG 13 and is usually configured to include an inverter or the like. The power from the battery 15 is supplied to the MG 13 or the battery 15 is charged with the generated power from the MG 13. To do.

  FIG. 2 shows a hybrid controller (hereinafter referred to as HEV controller) 21 for controlling the hybrid system. The HEV controller 21 receives signals such as a driving force request command and a vehicle speed, and the HEV controller 21 receives the driving force of the driver. According to demand, the driving force distribution between the engine 11 and the MG 13 is determined so as to obtain the best fuel consumption. These distributions are stored in the HEV controller 21 as a normal shift map. Similarly, a shift map prioritizing power generation for efficient charging during traveling is stored. For example, in the shift map for normal use, the engine 11 is operated so as to achieve the best fuel consumption, and a gear stage suitable for supplementing the shortage with the MG 13 is selected. Similarly, the shift map for power generation priority is selected so as to satisfy the driving force requirement and the power generation amount when the engine 11 is operated at the best fuel efficiency. And this control signal is output to the engine control part 26 and the MG control part 27, and the operation | movement of the engine 11 and MG13 is controlled based on these.

  The HEV controller 21 also includes a battery management unit 22 and a traveling charge control unit 23 for controlling the charging of the battery 15 whose amount of charge has decreased, particularly when the amount of charge of the battery 15 has decreased during traveling of the vehicle. And.

  The battery management unit 22 grasps and manages the state of the battery 15 based on the SOC (charge state) information of the battery 15, and when the SOC falls below a specified value, a charge request for causing the MG 13 to perform a power generation operation is performed during that time. To the unit 23.

  A shift map 24 is provided to control the shift of the transmission 12, and a shift stage is commanded according to a pre-mapped characteristic based on the required driving force and the vehicle speed. In response to the command of the shift map 24, the shift control unit 25 generates a command required for the shift to the shift actuator 28 that controls the shift position of the transmission 12, and at the same time, the shift command is transmitted to the engine control unit 26 and the MG control. Also sent to part 27.

  By the way, when a charge request is output from the battery management unit 22 to the running charge control unit 23, the shift map 24 is switched to the shift map for power generation priority, and a shift is performed by this switching. The traveling charge control unit 23 gives a command to the shift control unit 25 and can directly control the shift operation regardless of the shift command from the shift map 24 and without causing the driver to feel uncomfortable. It has become.

  In addition, the traveling charge control unit 23 gives a torque command to the engine control unit 26 and the MG control unit 27 after the shift operation so as to provide a good acceleration feeling immediately after the shift.

  Hereinafter, the charging control during traveling of the vehicle according to the present invention will be described with reference to the flowcharts of FIGS. 4 and 5.

  In FIG. 4, when the battery SOC becomes equal to or less than the specified value in step S100 and there is a charging request, the shift map 24 is switched to a power generation priority shift map, and the process proceeds to step S101 to determine whether a shift is necessary. . When it is determined that the shift is made by switching to the power generation priority shift map, the T / M shift control unit 25 is controlled by the running charge control unit 23 regardless of the command of the shift map 24.

Here, the shift by switching of the shift map 24 mainly occurs when the surplus torque of the engine 11 is insufficient. The engine 11 running on the normal shift map is operated at the best fuel efficiency, but has a torque that can be increased without changing the engine speed as a surplus torque. This is realized by controlling the fuel injection amount of the engine, which is a well-known technique. In other words, if the power generation torque of the MG 13 is within the range of the surplus torque, even if the shift map 24 is switched to the power generation priority shift map, power generation is performed with the surplus torque, and the rotational speed of the engine 11 does not change, so no shift occurs. However, if the power generation torque is equal to or greater than the surplus torque, it is necessary to shift the gear ratio to the low side to increase the engine surplus torque, and a shift occurs as the shift map is switched. Further, when the surplus torque is actually generated, the fuel consumption of the engine 11 is deteriorated. Therefore, even if the power generation torque is less than the surplus torque, the fuel consumption of the engine 11 is improved by actively shifting the gear ratio to the low side. In some cases, shifting may be performed.
In any case, if it is determined in step S101 that a shift occurs, the process proceeds to step S102. If it is determined that no shift occurs, the process proceeds to step S107, and the shift map 24 performs subsequent control based on the power generation priority map. And charge.
In step S102, a power generation command is output from the traveling charge control unit 23 to the MG control unit 27 so that the MG 13 performs initial power generation with a predetermined power generation torque. That is, the engine output is consumed with the initial power generation operation by the MG 13, and the driving force of the vehicle is reduced. In order to prevent the driver from feeling the deceleration at this time as a shock, the deceleration due to the power generation torque is generally Therefore, the power generation torque corresponding to the deceleration is set to be 0.10 m / s2 smaller than 0.015 m / s2, which is the minimum deceleration sensed by a person. The power generation torque can also be a value corresponding to an operating load of an auxiliary machine such as an air conditioner or a running resistance when the vehicle runs on a gentle climbing gradient (gradient less than 1%).

  As described above, by setting the power generation torque of the MG 13, a gentle deceleration feeling is given to the vehicle. Note that the power generation torque of the MG 13 may be a surplus torque added with a power generation torque that gives a gentle feeling of deceleration. In this case, if the torque of the engine 11 is increased by the surplus torque and the power generation torque of the MG 13 is made by adding the power generation torque that gives a gentle deceleration feeling to the surplus torque, a gentle deceleration feeling can be given while performing power generation. it can.

  If the vehicle has a moderate feeling of deceleration, the driver may depress the accelerator pedal to make a request for an increase in driving force, that is, an acceleration request.

  In step S103, it is determined whether or not an acceleration request command is issued from the driver. If there is an acceleration request, the process proceeds to step S104 to enter the shift control shown in FIG.

  On the other hand, when there is no acceleration request from the driver, the vehicle speed is compared with a threshold value based on a normal shift map in step S105. Even if the driver's request for driving force is constant, the vehicle driving force is reduced by the power generation of the MG 13 accompanying the charging control during traveling, the vehicle speed is gradually reduced, and the normal shift map 24 is set. When the vehicle speed reaches a predetermined vehicle speed at the shift speed, a shift command (shift down) by the normal shift map 24 is output. In this case, since the downshift is based on a decrease in vehicle speed, the driver feels uncomfortable.

  In this case, the process proceeds to step S104 and shift control is entered.

  If the vehicle speed is not less than or equal to the threshold value, the process proceeds to step S106 to determine whether or not the SOC state of the battery 15 is greater than or equal to the predetermined threshold value. If not, the process returns to step S103 and the above-described operation is repeated. That is, if the SOC of the battery 15 is restored to the specified value due to the power generation during the control of the MG 13, the process proceeds to step S108 and the running charging control is terminated.

  Next, the shift control performed in step S104 will be described with reference to FIG.

  In the shift control in step S104, when a shift request is first output, the power generation torque of the MG 13 is reduced in step S111.

  In step S112, the MG 13 selects a gear position that can ensure a predetermined marginal driving force even if power generation corresponding to the charging request is performed. That is, the gear position is determined based on the shift map for power generation priority. For example, in the case of FIG. 3, since driving is performed at point A of the 6th speed, the shift speed of point B, that is, the 3rd speed is selected as the vehicle driving force that can ensure a sufficient driving force.

  In step S113, the shift actuator 28 is commanded to change to the third speed, and the shift down is performed while controlling the starting clutch and the dog clutch.

  In step S114, torque assist by the MG 13 is controlled during this shift. Regardless of AT or AMT, in a stepped transmission, the transmission of torque temporarily decreases during the shift of the shift stage. At this time, torque assist by the MG 13 improves the shift quality of the transmission. . Since the shift time is very short, the power consumed by the MG 13 is sufficiently smaller than the remaining battery power and does not promote the deterioration of the battery 15.

  In step S115, the output torque of the engine 11 is increased. As a result, the driving force is increased more than before the shift, and the vehicle is accelerated.

  In step S116, it is determined whether or not the acceleration request from the driver has stopped. Since the driving force is increased by the downshift and the vehicle is accelerated, the driver stops the acceleration command when the desired vehicle speed is reached.

  While the acceleration is insufficient, the process returns to step S112, the above operation is repeated, and a lower gear (for example, the second gear) is selected. When the acceleration request is stopped, the process proceeds to step S117, and the torque of the engine 11 is adjusted.

  As the engine is downshifted, the rotational speed of the engine 11 is increased, the torque is increased, and the engine noise is larger than before the shift. If the driver shifts to the on-the-run charging control in a state where the acceleration request is stopped, the correlation between the driving force command and the engine sound cannot be obtained, and the driver may feel uncomfortable. For this reason, the engine torque is lowered to some extent and the engine noise is reduced, and then the shift to the running charging control is performed.

  In step S118, power generation by the MG 13 is performed in response to the charge request, and power generation torque is generated. That is, the power generation torque determined according to the power generation priority shift map. In this case, since the marginal driving force is increased due to the shift down, the traveling driving force does not decrease even if it corresponds to the charging request. However, the power generation torque according to the charging request at this time is within a range in which the vehicle driving force after the downshift is not smaller than the vehicle driving force before the shift. That is, in the shift map for power generation priority, it is possible to select the operating point of the engine 11 with the highest fuel efficiency when the output of the engine 11 is consumed with the required driving force and power generation torque. Thus, it is possible to generate power with high fuel efficiency while ensuring the travel drive characteristics.

After the shift stage for charging during traveling is determined, the process proceeds to step S107 in FIG. 4 to determine whether or not the battery SOC is equal to or greater than a predetermined threshold (predetermined value) based on the shift map for power generation priority. The charging control is continued until the value reaches or exceeds the value, and thereafter, the process proceeds to step S108 to end the charging.
After charging is completed, the power generation priority shift map is switched to the normal shift map, but the shift that can occur at this time is an upshift, and the shift shock is small, so the shift map is quickly switched to the normal shift map. It is done.

  Here, referring to the time chart of FIG. 6, an overall operation state of the charging control during traveling will be described.

  When the SOC of the battery 15 falls below a predetermined value during traveling of the vehicle, a charge request is issued and the initial power generation operation of the MG 13 is performed. The power generation torque at this time is set to be a small deceleration that does not cause the driver to feel a shock within the range of the engine surplus torque, but a part of the engine output is the power generation torque of the MG13. As the vehicle is consumed, the driving force of the vehicle decreases, and the vehicle speed gradually decreases accordingly.

  When the driver issues an acceleration request due to a decrease in the vehicle speed and the required driving force increases, the stepped transmission 12 enters a shift operation, and the shift speed is shifted down to a low speed. At this time, until the shift is completed, the MG 13 instantaneously reduces the generated torque, and then generates torque as a motor to perform torque assist. As a result, a decrease in vehicle driving force is suppressed despite a decrease in engine torque during shifting. The downshift is completed, the low speed stage is selected, and the engine output is also increased. As a result, the driving force of the vehicle is increased and the marginal driving force is sufficiently increased.

  In this state, the MG 13 generates power with the amount of power generated according to the request for charging the battery 15, and the battery 15 is quickly charged accordingly.

  As described above, according to the present embodiment, when the SOC of the battery 15 is reduced while the vehicle is running and charging is required, the vehicle 11 is small enough not to feel a deceleration shock within the surplus torque of the engine 11. Due to the power generation torque, the MG 13 enters the initial power generation operation. Along with this, the driving force of the vehicle relatively decreases. When the driver senses a decrease in the vehicle speed and outputs a driving force increase (acceleration) request, the stepped transmission 12 does not depend on the shift map. Then, a downshift is performed to generate a sufficient driving force, and thereafter, the MG 13 generates power with a power generation torque corresponding to the charging request. For this reason, even when there is a request for charging during driving, the driver is not discomforted, in other words, the driver is encouraged to downshift according to his / her own will, generating a surplus torque necessary for power generation, and promptly The battery 15 can be charged.

  Further, during the charging control, while the driver requests acceleration, further downshifting is performed, so that the charging request is from any driving state regardless of the vehicle speed or gear position. However, it is possible to appropriately provide a marginal driving force necessary for power generation, and to perform charge control with good responsiveness without giving the driver a sense of incongruity.

  Further, at the time of shifting the gear stage in response to the charging request, the torque assist of the MG 13 is performed to compensate for the decrease in the transmission torque during the shift, so that the torque shock during the shift is small and the shift characteristics can be improved.

  In addition, the decrease in vehicle driving force due to the power generation of the MG 13 due to the need for charging is small, and therefore the acceleration request required by the driver is moderate. Since it is slightly reduced, the surplus driving force is made to correspond to the power generation request of the MG 13, and the engine sound does not become excessive and does not cause a sense of incongruity than the engine sound assumed by the driver.

  It is obvious that the present invention is not limited to the above-described embodiments, and includes various changes and improvements that can be made by those skilled in the art within the scope of the claims.

  The present invention can be applied to a control device for a hybrid vehicle.

It is a block diagram which shows an example of the drive system in embodiment of this invention. It is also a block diagram of the control system. It is explanatory drawing which shows a driving force characteristic. It is a flowchart which shows control operation. It is a flowchart which similarly shows a control operation. It is a time chart which shows the operation characteristic at the time of power generation demand.

Explanation of symbols

11 Engine 12 Stepped Transmission 13 Motor Generator (MG)
14 Inverter 15 Battery 16 Output shaft 18 Drive wheel 21 Hybrid controller (HEV controller)
DESCRIPTION OF SYMBOLS 22 Battery management part 23 Charge control part during driving | running | working 24 Shift map 25 Shift control part 26 Engine control part 27 MG control part

Claims (6)

Engine,
A stepped transmission connected to the engine;
A motor generator for generating electricity by regenerating a part of the output of the engine;
In a hybrid vehicle drive control device comprising a battery that stores regenerative power of the motor generator,
A normal shift map for selecting the gear position of the stepped transmission based on the driving force requirement of the driver;
A power generation priority shift map for selecting the gear position of the stepped transmission based on the driver's driving force request and the power generation amount of the motor motor generator;
When the charge state of the battery decreases during traveling with reference to the normal shift map, and charging is required,
The motor generator is operated for initial power generation,
When a driving force increase request from the driver is output, the stepped transmission is shifted to the low speed side with reference to the power generation priority shift map, and the initial power generation operation is performed in response to the battery charging request. A drive control device for a hybrid vehicle, comprising: a charge control unit that changes the power generation operation to a power generation operation of the motor generator.   The initial power generation operation of the motor generator is any of the following conditions: a driving force acceleration request from the driver, a shift request based on a normal shift map of the stepped transmission, or the battery charge state is restored to a specified value The drive control apparatus for a hybrid vehicle according to claim 1, which is continued until is established.   The drive control apparatus for a hybrid vehicle according to claim 1 or 2, wherein the power generation torque of the initial power generation operation of the motor generator is set to a value corresponding to an auxiliary machine drive load or a gentle gradient resistance during uphill travel.   The drive control device for a hybrid vehicle according to any one of claims 1 to 3, wherein a shift operation to the further low speed side of the shift stage is continued while the driving force request from the driver is continued. .   The drive control apparatus for a hybrid vehicle according to any one of claims 1 to 4, wherein during the speed change operation of the stepped transmission, the motor generator is driven by a motor to perform torque assist.   The drive control apparatus for a hybrid vehicle according to any one of claims 1 to 5, wherein the engine torque is slightly reduced immediately after the end of the speed change operation of the stepped transmission.

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