JP2004011486A - Hybrid vehicle and its control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To find a difference between target torque and actual torque in a hybrid vehicle and correct the distribution of engine torque depending on the operated condition of the vehicle when the difference exists. <P>SOLUTION: The hybrid vehicle has the engine 2 and a motor generator 5 to be driven by the engine for functioning power generation. It comprises target engine torque computing means 13 for computing target engine torque in accordance with target driving force and target generating torque of the vehicle, torque distributing means 13 for distributing the engine torque into the target driving force and the target generating torque, torque difference computing means 13 for calculating a difference between the computed target engine torque and actual engine torque, and preferential operated condition determining means 13 for determining a preferential operated condition of the operated conditions of the vehicle. The torque distributing means 13 corrects the distribution of the engine torque depending on the preferential operated condition when a difference exists between the target engine torque and the actual engine torque. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hybrid vehicle and a control device thereof.
[0002]
[Prior art]
As a technique related to a conventional hybrid vehicle, there is one described in Japanese Patent Application Laid-Open No. 2000-115908. According to this technology, when the charge rate of a battery is low, the engine is operated as a drive source of a vehicle, and the engine generates electric power from a motor / generator (hereinafter, referred to as M / G) to increase the charge rate of the battery. A mode, an accelerated running mode in which the vehicle is accelerated by using the engine and the M / G as driving sources when the battery charging rate is high and the accelerator change amount (or rate of change) is large, Also disclosed is a hybrid vehicle having an engine traveling mode in which the vehicle travels using only the engine as a drive source when the accelerator change amount is small.
[0003]
[Problems to be solved by the invention]
However, in the prior art, the engine output torque (target driving torque of the vehicle + generation torque) may not reach the target torque due to a response delay or the influence of the external environment. Under such circumstances, the battery cannot be sufficiently charged. May not be done.
[0004]
Therefore, an object of the present invention is to provide a hybrid vehicle that calculates a difference between a target torque and an actual torque and, when there is a difference, corrects the distribution of engine torque according to the operating state of the vehicle.
[0005]
[Means for Solving the Problems]
The present invention relates to a hybrid vehicle including an engine for driving a vehicle, a function of generating power by driving the engine, and a motor generator having a function of driving the vehicle, based on a target driving force and a target power generation torque of the vehicle. Target engine torque calculating means for calculating a target engine torque; torque distributing means for distributing the engine torque to a target driving force and a target power generation torque; and a torque for calculating a difference between the calculated target engine torque and the actual engine torque. A difference operation unit, and a priority operation state determination unit that determines an operation state to be prioritized in the operation state of the vehicle, wherein the torque distribution unit has a priority when a difference between the target engine torque and the actual engine torque exists. The distribution of the engine torque is corrected according to the operating state.
[0006]
【The invention's effect】
According to the present invention, the engine torque distribution distributed between the target driving force and the target power generation torque is corrected according to the priority operation state when there is a difference between the target torque and the actual engine torque. It can approach or achieve the target performance. Specifically, for example, when the driving force is requested in the power generation torque priority state and the torque is distributed only to the driving force, the SOC of the battery decreases, the idle stop state decreases, and the fuel efficiency improves. However, in the present invention, it is possible to prevent the SOC from decreasing by increasing the distribution of the generated torque. In the driving force priority state in which the driving force is prioritized, by increasing the torque distribution to the driving force, the driving force can be increased and the target acceleration performance can be achieved.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
An outline of a hybrid vehicle to which the present invention is applied will be described with reference to FIG.
[0008]
The hybrid vehicle includes an engine 2 as a drive source for driving the rear wheels 1, a transmission 3 for transmitting the driving force of the engine 2 to the rear wheels 1, a differential gear 4, and the like. Further, a first M / G 5 is provided between the engine 2 and the transmission 3, and the first M / G 5 functions only as a motor at the time of starting and creep running, or as a generator connected via the inverter 6. 7 functions to increase the charge amount of the battery when the charge amount is small.
[0009]
Further, a second M / G 8 operated by power supply from the battery 7 is provided as a drive source for driving the front wheels, and when driving only the rear wheels, the second M / G 8 functions as a generator. It is possible to charge. The driving force distribution to the front and rear wheels during normal traveling is set to be an optimal driving force distribution according to road surface conditions, traveling conditions, and the like.
[0010]
The engine 2, the first and second M / Gs 5 and 8, and the transmission 3 are controlled by signals transmitted from the respective controllers 9 to 12. Control information from a control module (hereinafter, referred to as HCM) 13 is sent to these controllers 9 to 12, and each controller controls the components based on this information.
[0011]
To calculate the control information, the HCM 13 includes a vehicle speed sensor (not shown), a rotation speed sensor for detecting the input / output rotation speed of the transmission 3, a rotation speed sensor for detecting the actual rotation speed of the engine, and a brake master cylinder pressure. Output signals from a sensor, a sensor for detecting the accelerator opening, and the like are input. The HCM 13 calculates and sets a torque corresponding to a target driving force of the engine 2 (hereinafter, simply referred to as a target driving force) and a target power generation torque based on these input signals.
[0012]
Next, a method of calculating the power generation torque value for M / G performed by the HCM 13 which is a feature of the present invention will be described with reference to FIG.
[0013]
To explain the outline of the control content of this flowchart, it is determined whether the actual torque of the engine is the target engine torque which is the sum of the target driving force and the target power generation torque, and if the actual torque does not reach the target engine torque, Calculates the shortfall. Here, the driving state of the vehicle is classified into conditions, for example, a driving force priority state in which driving force such as acceleration is prioritized, a power generation torque priority state in which power generation is prioritized, and the like. Then, the ratio between the target driving force and the target power generation torque is corrected according to the operation state. As an example, when the operation state is the power generation torque priority state, of the actual engine torque, the distribution of the target power generation torque is increased (at most the target power generation torque), and the remaining torque is allocated to the driving force. . Therefore, the generated power is preferentially secured, and the generated power is maintained at the maximum at the target power generation torque, so that the SOC of the battery 7 can be quickly increased.
[0014]
Hereinafter, the calculation of the power generation torque will be described.
[0015]
First, in step 1, a target engine torque TTEN is obtained by adding the target driving force TTEDD of the vehicle and the target power generation torque TTENS, and the actual engine torque STEN is subtracted from the previous value of the target engine torque TTEN, and the difference DTTEN is calculated. Calculate.
[0016]
In step 2, the target engine torque value TTEN is compared with the maximum engine torque value MAXTRQ. If the target engine torque value TTEN is large, the process proceeds to step 3, otherwise the process proceeds to step 4.
[0017]
In step 3, the target engine torque value TTEN is set as the engine torque maximum value MAXTRQ.
[0018]
In step 4, a vehicle acceleration determination flag fDYNAMIC, which is set by a driving force priority determination described later, is determined. If flag = 1, it is determined that the vehicle is accelerating, and the process proceeds to step 6, and if flag = 0, the process proceeds to step 5. Then, the accelerator opening APO is determined. If the accelerator opening flag fFLSWPT, which is set based on the output of the accelerator opening sensor, is 1, indicating that the accelerator pedal is fully open, the process proceeds to step 6, otherwise, the process proceeds to step 7. Therefore, even if the flag fDYNAMIC = 1 indicating the acceleration state is not set, it is possible to determine from the accelerator opening degree that the driver requests acceleration and control the acceleration state.
[0019]
In step 6, the driving force priority condition flag fDRVPRIO is set to 1 as the driving state of the vehicle in which the driving force should be prioritized. On the other hand, in step 7, the driving force priority condition flag fDRVPRIO is set to 0 assuming that the vehicle is not in a state where the driving force should be prioritized.
[0020]
In Step 8, it is determined whether the driving force priority condition flag fDRVPRIO is 0 and the power generation request flag fGENUPRQ0 is 1. The case where the power generation request flag fGENUPRQ0 becomes 1 is, for example, a case where the SOC of the battery 4 falls below a predetermined remaining capacity. If the condition is satisfied, the process proceeds to step 9, and if not, the process proceeds to step 10. By determining the power generation request state based on the SOC of the battery 4, it is possible to prevent the SOC from being significantly lower than the predetermined remaining capacity.
[0021]
In step 9, the power generation priority condition flag fGENPRIO is set to 1 assuming that the driving state of the vehicle should prioritize the power generation torque, and in step 10, the power generation priority condition flag fGENPRIO is set to 0.
[0022]
In a succeeding step 11, it is determined whether or not the driving force priority condition flag fDRVPRIO is 1. When the flag is 1, the process proceeds to step 12, and when the flag is 0, the process proceeds to step 13.
[0023]
In step 12 when the flag = 1, the power generation torque calculation coefficient KDTTEN is calculated as the driving force priority state. The power generation torque calculation coefficient KDTTEN is a smaller value of a value obtained by adding the previous value KDTTENz of the power generation torque calculation coefficient and the transition rate DKDTTEN1 of the power generation torque calculation coefficient and a constant 1. That is, the power generation torque calculation coefficient KDTTEN is 1 at the maximum. Here, the transition rate DKDTTEN is a power generation torque calculation coefficient, that is, a constant used to gradually change the power generation torque to the power generation torque priority state side so that the power generation torque does not suddenly change and the operability becomes unstable. Value. By setting the predetermined transition rate, the power generation torque calculation coefficient KDTTEN changes stepwise in each calculation cycle, and for example, it is possible to prevent a sudden change in the driving force and a shock to the driver.
[0024]
After calculating the power generation torque calculation coefficient KDTTEN, the routine proceeds to step 14, where the calculation of the M / G power generation motor torque value TTMG1 is performed. The power generation motor torque value TTMG1 is calculated by subtracting a value obtained by multiplying the power generation torque calculation coefficient KDTTEN by the difference DTTEN calculated in step 1 from the target power generation torque TTENS.
[0025]
That is, when the operating state is the driving force priority state, the difference DTTEN is reduced at most from the target power generation torque, and the power generation motor torque value TTMG1 becomes (target power generation torque TTENS-difference DTTEN). On the other hand, since the target driving force cancels the difference between the target engine torque and the actual engine torque by reducing the power generation torque, the desired vehicle acceleration performance can be secured without reducing the target driving force at the maximum. .
[0026]
On the other hand, if the driving force priority condition flag fDRVPRIO is 0 in step 11, the process proceeds to step 13, and it is determined whether the power generation priority condition flag fGENPRIO is 1. If the flag is 1, the routine proceeds to step 15, where the power generation torque calculation coefficient KDTTEN is calculated. Here, the power generation torque calculation coefficient KDTTEN is set to a larger value between 0 and a value obtained by subtracting the transfer rate DKDTTEN2 of the power generation torque calculation coefficient from the previous value KDTTENz of the power generation torque calculation coefficient. After the calculation of the power generation torque calculation coefficient KDTTEN is completed, the process proceeds to step 14, where the calculation of the M / G power generation motor torque value TTMG1 is performed.
[0027]
That is, when the operation state is the power generation torque priority state, the target power generation torque can maintain the target power generation torque TTEN without subtracting the maximum difference DTTEN from the target power generation torque. Therefore, power generation can be performed as required, and the SOC of the battery 7 can be quickly increased to a predetermined level.
[0028]
If the power generation priority condition flag fGENPRIO is 0, that is, if the driving power is not in the priority state and the power generation torque is not in the priority state, the process proceeds to step 16, and the previous value KDTTENz of the power generation torque calculation coefficient is calculated as the difference DTTEN in step 1. It is determined whether it is equal to or greater than the value obtained by dividing the target engine torque value TTEN. If the condition is satisfied, the process proceeds to step 17, and if not, the process proceeds to step 18.
[0029]
In step 17, a power generation torque calculation coefficient KDTTEN is calculated. The generated torque calculation coefficient KDTTEN is calculated by comparing a value obtained by subtracting the transition rate DKDTTEN3 of the generated torque calculation coefficient from the previous value KDTTENz of the generated torque calculation coefficient with a value obtained by dividing the difference DTTEN by the target engine torque value TTEN. The value is set as the power generation torque calculation coefficient KDTTEN.
[0030]
On the other hand, in step 18, the power generation torque calculation coefficient KDTTEN is calculated as follows. A value obtained by adding the previous value KDTTENz of the power generation torque calculation coefficient and the transition rate DKDTTEN4 of the power generation torque calculation coefficient is compared with a value obtained by dividing the difference DTTEN by the target engine torque value TTEN, and the smaller value is used as the power generation torque calculation coefficient KDTTEN. Set as
[0031]
Therefore, when the driving state is neither the driving force priority state nor the power generation torque priority state, the power generation torque calculation coefficient KDTTEN is set to a value calculated by dividing the difference DTTEN by the target engine torque, that is, the target driving force and the target power generation torque. Therefore, when the difference between the actual engine torque and the target engine torque is small, it is possible to achieve an appropriate engine torque distribution, for example, to prevent an excessive shortage of power generation torque due to giving priority to the torque to the driving force side. .
[0032]
When the generation torque calculation coefficient KDTTEN has been set in steps 17 and 18, the process proceeds to step 14, where the M / G power generation motor torque value TTMG1 is calculated, and the control is terminated.
[0033]
Next, the driving force priority determination for setting the acceleration determination flag fDYNAMIC will be described with reference to FIG. 3 and a flowchart of FIG. 4 described later are calculated by the HCM 13 in parallel with the flowchart of FIG.
[0034]
In step 20, the change rate of the accelerator operation amount APO is calculated from the difference between the operation amount at the time of this control and the previous operation amount, and this change rate is compared with a reference change rate mDAPOLMT for acceleration determination. If the comparison result is equal to or greater than the reference change rate mDAPOLMT, the process proceeds to step 21; otherwise, the process proceeds to step 22. Here, the change rate of the accelerator operation amount APO is used as the determination condition, but the determination may be made using the magnitude of the accelerator operation amount APO. As described above, by performing the acceleration determination using the magnitude of the accelerator operation amount APO or the rate of change thereof, it is possible to quickly determine the driver's intention to accelerate.
[0035]
In step 21, the driving force tmp for the running resistance is calculated using a vehicle speed-driving resistance equivalent driving force table as shown in FIG. In the following step 23, it is determined whether or not a value obtained by subtracting the driving force tmp from the target driving force TFDD from the target driving force TFDD is equal to or greater than an acceleration driving force determination value mTRLFDHYS. Proceed to step 22.
[0036]
In step 22, the acceleration condition flag fDYNAMIC1 is set to 0 as not satisfying the acceleration condition, and in step 24, the acceleration condition flag fDYNAMIC1 is set to 1 to satisfy the acceleration condition.
[0037]
In step 25, it is determined whether the previous acceleration condition flag fDYNAMIC1z is 0 and the current acceleration condition flag fDYNAMIC1 is 1. When this condition is satisfied, the routine proceeds to step 26, where the acceleration determination timer tTIMER1 is set to the acceleration determination timer set value mTIMER1, and the routine proceeds to step 27. If not, the process proceeds to step 27. Here, when the acceleration determination is different from that in the previous calculation cycle, the acceleration determination timer tTIMER1 is set to a predetermined acceleration determination timer set value mTIMER1, and the timer control shown in FIG. 5 is performed.
[0038]
In step 27, it is determined whether or not an acceleration determination timer tTIMER1 described in FIG. If it is 0, the process proceeds to step 28, where the acceleration determination flag fDYNAMIC is set to 0, and the control is terminated. If the acceleration determination timer tTIMER1 is other than 0, the process proceeds to step 29, where the acceleration determination flag fDYNAMIC is set to 1, and the control ends.
[0039]
The setting of the acceleration determination timer tTIMER1 shown in FIG. 5 will be described.
[0040]
First, in step 30, the countdown of the acceleration determination timer tTIMER1 is started. The start of the countdown is started when the condition of step 23 is satisfied.
[0041]
Next, at step 31, it is determined whether or not the acceleration determination timer tTIMER1 is smaller than 0. If it is smaller, the process proceeds to step 32, where 0 is set as the acceleration determination timer tTIMER1. If it is 0 or more, the control is repeated as it is.
[0042]
That is, the acceleration state (driving force priority state) is prioritized until the acceleration determination timer tTIMER1 becomes 0 in step 27 after the acceleration determination timer set value mTIMER1 is set in the acceleration determination timer tTIMER1 in step 26 shown in FIG.
[0043]
Therefore, in the hybrid vehicle, when the battery needs to be charged or when the drive wheels driven only by the motor are used, a request for the power generation torque is generated, and the power generation torque priority state is set. In this case, when the driving force is required and the torque is distributed only to the driving force, the SOC of the battery decreases, the idle stop state decreases, and the fuel consumption improvement margin decreases. In the present invention, the difference between the target engine torque and the actual engine torque is determined, and the distribution of the driving force and the power generation torque is appropriately corrected according to the torque difference and the priority operation condition (for example, in the power generation torque priority state, the power generation torque By increasing the distribution of power), the generation torque is not significantly reduced, and a decrease in SOC can be suppressed.
[0044]
On the other hand, in the driving force priority state where driving force is required, by increasing the torque distribution to the driving force, the driving force can be increased and the target acceleration performance can be achieved.
[0045]
When it is not possible to select whether to give priority to the driving force or the generation torque (third priority state), the distribution of the driving force and the generation torque is set based on the target driving force and the target generation torque. Shortage of torque can be prevented, and appropriate engine torque can be distributed.
[0046]
The torque distribution in each priority state changes stepwise to another priority state at a predetermined transition rate in each calculation cycle, thereby suppressing sudden changes in drive torque and preventing shocks due to changes in drive force. I do.
[0047]
In the driving force priority determination, the driver's acceleration intention is grasped based on the accelerator opening APO, and the driving force priority state is determined. When the driving force priority state is determined, the distribution of the driving force is increased, and the power generation torque is increased. Decrease minutes. This driving force priority state is maintained for a predetermined time from the time when the throttle opening is changed to the time when the actual engine torque is increased, in other words, a time in which the influence of the dead time and the first-order lag is large. Therefore, during the time when the influence of the dead time and the first-order lag is large, the torque response to the power generation request of the motor is faster than the torque response to the driving force request, and thus the driving force is significantly reduced by securing the generated torque as required. In addition, it is possible to prevent the torque required for the engine from running up. As a result, it is possible to suppress a decrease in the target driving force and to secure a torque that satisfies the driver's acceleration request.
[0048]
The present invention is not limited to the above-described embodiments, and it is apparent that various changes can be made within the scope of the technical idea of the present invention.
[Brief description of the drawings]
FIG. 1 is a system schematic diagram of a hybrid vehicle to which the present invention is applied.
FIG. 2 is a flowchart of a motor generation torque value calculation.
FIG. 3 is a flowchart of driving force priority determination.
FIG. 4 is an example of a map for calculating running resistance.
FIG. 5 is a flowchart of a timer control.
[Explanation of symbols]
2 engine 3 continuously variable transmission 4 motor generator 7 battery 13 HCM

Claims (8)

An engine that drives the vehicle,
In a hybrid vehicle having a function of generating power by being driven by the engine and a motor generator having a function of driving the vehicle,
Target engine torque calculating means for calculating a target engine torque based on a target driving force and a target power generation torque of the vehicle;
Torque distribution means for distributing the engine torque between the target driving force and the target power generation torque,
Torque difference calculating means for calculating a difference between the calculated target engine torque and the actual torque of the engine;
Priority driving state determination means for determining a driving state to be prioritized in the driving state of the vehicle,
A hybrid vehicle according to claim 1, wherein said torque distribution means corrects the distribution of the engine torque according to the priority driving state when there is a difference between the target engine torque and the actual engine torque. 2. The hybrid vehicle according to claim 1, wherein the priority state determination unit determines from a driving force priority state of the vehicle, a power generation torque priority state, and a third priority state other than these. 3. The hybrid vehicle according to claim 2, wherein in the third priority state, the distribution of the engine torque is set according to the target driving force and the target power generation torque. The hybrid vehicle according to any one of claims 1 to 3, wherein the distribution of the engine torque is changed stepwise each time the priority state is determined. The hybrid vehicle according to any one of claims 1 to 4, wherein the priority state determination unit determines the driving force priority state when an amount of depression of an accelerator pedal or a depression speed is equal to or more than a predetermined value. The hybrid vehicle according to claim 5, wherein when the driving force priority state is determined, the driving force priority state is maintained for a predetermined time after the determination. The hybrid vehicle according to any one of claims 1 to 6, wherein the priority state determination means determines the power generation torque priority state when the remaining capacity of the battery is equal to or less than a predetermined value. An engine that drives the vehicle,
In a hybrid vehicle having a function of generating power by being driven by the engine and a motor generator having a function of driving the vehicle,
Target engine torque calculating means for calculating a target engine torque based on a target driving force and a target power generation torque of the vehicle;
Torque distribution means for distributing the engine torque between the target driving force and the target power generation torque,
Torque difference calculating means for calculating a difference between the calculated target engine torque and the actual torque of the engine;
Priority driving state determination means for determining a driving state to be prioritized in the driving state of the vehicle,
The control device for a hybrid vehicle, wherein the torque distribution unit corrects the distribution of the engine torque according to the priority driving state when there is a difference between the target engine torque and the actual engine torque.

Images