JP3894049B2 - Hybrid vehicle and its control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hybrid vehicle and its control device.
[0002]
[Prior art]
Japanese Unexamined Patent Publication No. 2000-115908 discloses a technique related to a conventional hybrid vehicle. In this technology, when the battery charge rate is low, the engine is operated as a vehicle drive source, and a motor / generator (hereinafter referred to as M / G) is generated by the engine to increase the battery charge rate. Mode, the battery charge rate is high, and when the accelerator change amount (or change rate) is large, the acceleration running mode for accelerating the vehicle using the engine and M / G as drive sources, and the battery charge rate is high, And the hybrid vehicle provided with the engine running mode which makes a vehicle drive | work only with an engine as a drive source when the amount of accelerator changes is small is disclosed.
[0003]
[Problems to be solved by the invention]
However, in the prior art, the engine output torque (target drive torque of the vehicle + power generation torque) may not reach the target torque due to the response delay or the influence of the external environment, and the battery is sufficiently charged under such circumstances. May not be done.
[0004]
Accordingly, an object of the present invention is to provide a hybrid vehicle that obtains a difference between a target torque and an actual torque and corrects the distribution of engine torque in accordance with the driving state of the vehicle when the difference exists.
[0005]
[Means for Solving the Problems]
The present invention relates to a hybrid vehicle including an engine for driving a vehicle, a function for generating electric power driven by the engine, and a motor generator having a function for driving the vehicle, based on the target driving force and the target power generation torque of the vehicle. Target engine torque calculating means for calculating the target engine torque, torque distribution means for distributing the engine torque to the target driving force and the target power generation torque, and torque for calculating the difference between the calculated target engine torque and the actual engine torque The driving state to be prioritized according to the difference calculation means, the accelerator opening or the opening change rate, and the battery SOC is determined from the driving force priority state, the power generation torque priority state, and the third priority state other than these. Priority operating state determination means, and the torque difference calculation means includes a target engine torque, an actual engine torque, If there is a difference and the driving state is the driving force priority state, the difference between the target engine torque and the actual engine torque is subtracted from the target power generation torque so as to maintain the target driving force. If there is a difference between the engine torque and the actual torque of the engine, and the operating state is the power generation torque priority state, the target power generation torque is maintained, and there is a difference between the target engine torque and the actual engine torque. If the operation state is the third priority state, the engine torque distribution is set according to the difference between the target engine torque and the actual engine torque, the target driving force, and the target power generation torque .
[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 set according to each priority operation state when there is a difference between the target torque and the actual engine torque. The target performance can be approached or achieved. Specifically, for example, driving force is required in the power generation torque priority state, and if the torque is distributed only to the driving force, the SOC of the battery is lowered, the idle stop state is reduced, and fuel consumption is improved. In the present invention, it is possible to prevent the SOC from decreasing by increasing the distribution of the power generation torque. Further, in the driving force priority state where the driving force is given priority, by increasing the torque distribution to the driving force, the driving force can be increased and the target acceleration performance can be achieved.
[0007]
DETAILED DESCRIPTION OF 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 wheel 1, a transmission 3 for transmitting the driving force of the engine 2 to the rear wheel 1, a differential gear 4, and the like. Further, a first M / G5 is installed between the engine 2 and the transmission 3, and the first M / G5 functions as a motor only at the start and during creep running, or as a generator, a battery connected via an inverter 6. 7 functions to increase the charge amount of the battery when the charge amount is small.
[0009]
A second M / G 8 that operates by supplying power from the battery 7 is installed as a drive source for driving the front wheels. When only the rear wheels are driven, the second M / G 8 functions as a generator, and the generated power is supplied to the battery 8. 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 the road surface condition, the traveling condition, and the like.
[0010]
Engine 2, first, second M / G 5, 8 and transmission 3 are controlled by signals transmitted from respective controllers 9-12. Control information from a control module (hereinafter referred to as HCM) 13 is sent to these controllers 9 to 12, and each controller controls components based on this information.
[0011]
In order to calculate the control information, the HCM 13 detects a vehicle speed sensor (not shown), a rotation speed sensor that detects the input / output rotation speed of the transmission 3, a rotation speed sensor that detects the actual rotation speed of the engine, and a brake master cylinder pressure. An output signal from a sensor, a sensor for detecting the accelerator opening, or the like is input. Based on these input signals, the HCM 13 calculates and sets a torque corresponding to the target driving force of the engine 2 (hereinafter simply referred to as a target driving force) and a target power generation torque.
[0012]
Next, a method for 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]
The outline of the control contents of this flowchart will be explained. When the actual torque of the engine is determined to be the target engine torque that is the sum of the target driving force and the target power generation torque, the actual torque does not reach the target engine torque. Calculates the shortage. Here, the driving state of the vehicle is divided into conditions, and is classified into, for example, a driving force priority state that prioritizes driving force such as acceleration, a power generation torque priority state that prioritizes power generation, and the like. Then, the ratio between the target driving force and the target power generation torque is corrected according to this operating state. As an example, when the operating state is the power generation torque priority state, control is performed so that the distribution of the target power generation torque in the actual engine torque is increased (maximum target power generation torque) and the remaining torque is allocated to the driving force. . Accordingly, the generated power is preferentially secured, and the generated power maintains the power generation amount of the target power generation torque at the maximum, so that the SOC of the battery 7 can be quickly increased.
[0014]
Hereinafter, calculation of the power generation torque will be described.
[0015]
First, in step 1, the target driving force TTETD and the target power generation torque TTENS of the vehicle are added to obtain the target engine torque value TTEN, and the actual engine torque STEN is subtracted from the previous value of the target engine torque value 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, the vehicle acceleration determination flag fDYNAMIC set by the driving force priority determination described later is determined. If flag = 1, it is determined that the vehicle is in an acceleration state, and the process proceeds to step 6. If flag = 0, the process proceeds to step 5. Then, the accelerator opening APO is determined. If the accelerator opening flag fFLSWPT set based on the output of the accelerator opening sensor is 1, indicating that the valve is fully open, the process proceeds to step 6; otherwise, the process proceeds to step 7. Accordingly, even if the flag fDYNAMIC = 1 indicating the acceleration state is not set, it is possible to determine that the driver requests acceleration based on the accelerator opening, and to control the acceleration state.
[0019]
In step 6, the driving force priority condition flag fDRVPRIO is set to 1 as a state in which the driving state of the vehicle should give priority to the driving force. 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 priority should be given to the driving force.
[0020]
In step 8, it is determined whether or not 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, when the SOC of the battery 4 falls below a predetermined remaining capacity. If the condition is satisfied, the process proceeds to step 9; otherwise, 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 give priority to the power generation torque, and in step 10, the power generation priority condition flag fGENPRIO is set to 0.
[0022]
In the following step 11, it is determined whether or not the driving force priority condition flag fDRVPRIO is 1. If the flag = 1, the process proceeds to step 12, and if the flag = 0, the process proceeds to step 13.
[0023]
In step 12 in the case of 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 set to a smaller value of a constant 1 and 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. That is, the power generation torque calculation coefficient KDTTEN is 1 at the maximum. Here, the transition rate DKDTTEN is a constant used for changing the power generation torque calculation coefficient, that is, the power generation torque, to the power generation torque priority state step by step so that the drivability does not become unstable and the drivability becomes unstable. The value of By setting the predetermined transition rate, the power generation torque calculation coefficient KDTTEN changes step by step for each calculation cycle, and for example, it is possible to prevent the driving force from changing suddenly and shocking the driver.
[0024]
After calculating the power generation torque calculation coefficient KDTTEN, the process proceeds to step 14 where the M / G power generation motor torque value TTMG1 is calculated. 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 driving state is the driving force priority state, the difference DTTEN is subtracted from the target power generation torque at maximum, 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 driving acceleration performance can be ensured 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 to determine whether the power generation priority condition flag fGENPRIO is 1. If the flag = 1, the process proceeds to step 15 to calculate the power generation torque calculation coefficient KDTTEN. Here, the power generation torque calculation coefficient KDTTEN is set to a larger value of 0 and a value obtained by subtracting the power generation torque calculation coefficient transition rate DKDTTEN2 from the previous value KDTTENz of the power generation torque calculation coefficient. When the calculation of the power generation torque calculation coefficient KDTTEN is completed, the process proceeds to step 14 where the M / G power generation motor torque value TTMG1 is calculated.
[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 TTENS without subtracting the difference DTTEN from the target power generation torque at the maximum. Therefore, power generation can be performed as required, and the SOC of the battery 7 can be quickly increased to a predetermined level.
[0028]
When the power generation priority condition flag fGENPRIO is 0, that is, when it is neither the driving force priority state nor the power generation torque priority state, the process proceeds to step 16 where the previous value KDTTENz of the power generation torque calculation coefficient is calculated as the difference DTTEN in step 1 It is determined whether or not the value is equal to or greater than the value divided by 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 power generation torque calculation coefficient KDTTEN compares the value obtained by subtracting the power generation torque calculation coefficient transition rate DKDTTEN3 from the previous value KDTTENz of the power generation torque calculation coefficient and the value obtained by dividing the difference DTTEN by the target engine torque value TTEN. The value is set as a 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. The 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 the value obtained by dividing the difference DTTEN by the target engine torque value TTEN, and the smaller value is compared with 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 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, appropriate engine torque distribution can be achieved, such as preventing excessive power generation torque shortage by giving priority to torque to the driving force side. .
[0032]
When the setting of the power generation torque calculation coefficient KDTTEN is completed in steps 17 and 18, the process proceeds to step 14, where the calculation of the M / G power generation motor torque value TTMG1 is performed, and the control ends.
[0033]
Next, the driving force priority determination for setting the acceleration determination flag fDYNAMIC will be described with reference to FIG. The flowchart of FIG. 3 and 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 during the current control and the previous operation amount, and this change rate is compared with the reference change rate mDAPOLMT for acceleration determination. If the comparison result is equal to or higher than the reference change rate mDAPOLMT, the process proceeds to step 21; otherwise, the process proceeds to step 22. Here, although the change rate of the accelerator operation amount APO is used as the determination condition, the determination may be made using the magnitude of the accelerator operation amount APO. Thus, by performing acceleration determination using the magnitude of the accelerator operation amount APO or its rate of change, the driver's intention to accelerate can be determined quickly.
[0035]
In step 21, a driving force tmp corresponding to the running resistance is calculated using a vehicle speed-running resistance equivalent driving force table as shown in FIG. In step 23, it is determined whether the value obtained by subtracting the driving resistance tmp from the target driving force TFDD is greater than or equal to the acceleration driving force determination value mTRLDFDHYS. If the condition is satisfied, the process proceeds to step 24. Proceed to step 22.
[0036]
In step 22, the acceleration condition flag fDYNAMIC1 is set to 0 assuming that the acceleration condition is not satisfied, and in step 24, the acceleration condition flag fDYNAMIC1 is set to 1 assuming that the acceleration condition is satisfied.
[0037]
In step 25, it is determined whether or not the previous acceleration condition flag fDYNAMIC1z is 0 and the current acceleration condition flag fDYNAMIC1 is 1. When this condition is satisfied, the process proceeds to step 26, the acceleration determination timer set value mTIMER1 is set in the acceleration determination timer tTIMER1, and the process proceeds to step 27. If not, the process proceeds to step 27. Here, when the acceleration determination is different from 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. In the case of 0, the process proceeds to step 28, 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, at step 30, the acceleration determination timer tTIMER1 starts to count down. The countdown starts 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, after the acceleration determination timer set value mTIMER1 is set in the acceleration determination timer tTIMER1 in step 26 shown in FIG. 3, the acceleration state (driving force priority state) is given priority until the acceleration determination timer tTIMER1 becomes 0 in step 27.
[0043]
Therefore, in the hybrid vehicle, when the battery needs to be charged or when driving wheels that are driven only by the motor are used, a request for power generation torque is generated, and the power generation torque priority state is set. In this case, the driving force is required, and if the torque is distributed only to the driving force, the SOC of the battery will be reduced, the idle stop state will be reduced, and the fuel savings will be reduced. In the present invention, the difference between the target engine torque and the actual engine torque is obtained, and the distribution of the driving force and the power generation torque is appropriately corrected according to the torque difference and the priority operation conditions (for example, in the power generation torque priority state, the power generation torque is The power generation torque is not significantly reduced and the reduction in the SOC can be suppressed.
[0044]
On the other hand, in the driving force priority state in which the 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]
In addition, when it is not possible to select whether to give priority to driving force or power generation torque (third priority state), the distribution of driving force and power generation torque is set based on the target driving force and target power generation torque. Torque shortage can be prevented and appropriate engine torque distribution can be performed.
[0046]
Torque distribution in each priority state changes step by step to another priority state at a predetermined transition rate for each calculation cycle, thus suppressing sudden changes in drive torque and preventing shocks associated with changes in drive force To do.
[0047]
In the driving force priority determination, the driver's intention to accelerate is grasped based on the accelerator opening APO and the driving force priority state is determined. If 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 when the throttle opening changes to when the actual engine torque increases, in other words, during a period of time that is largely affected by dead time and primary delay. Therefore, since the torque response to the power generation request of the motor is faster than the torque response to the driving force request at the time when the influence of the dead time and the first order delay is large, the driving force is significantly reduced by securing the power generation torque as required. In addition, it is possible to prevent the torque necessary for the engine from running out. As a result, it is possible to suppress a decrease in the target driving force and secure a torque that satisfies the driver's acceleration request.
[0048]
The present invention is not limited to the above-described embodiment, and it is obvious that various modifications 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 for calculating a power generation torque value for a motor.
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 timer control.
[Explanation of symbols]
2 Engine 3 Continuously variable transmission 4 Motor generator 7 Battery 13 HCM

Claims (6)

An engine that drives the vehicle;
In a hybrid vehicle having a function of generating electric power 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 the target driving force and the target power generation torque of the vehicle;
Torque distribution means for distributing engine torque to target driving force and target power generation torque;
Torque difference calculating means for calculating a difference between the calculated target engine torque and the actual engine torque;
Priority operating state determination means for determining an operating state to be prioritized according to the accelerator opening or the opening change rate and the battery SOC from the driving force priority state, the power generation torque priority state, and a third priority state other than these. And
When the difference between the target engine torque and the actual engine torque exists and when the driving state is the driving force priority state, the torque difference calculation means is configured to maintain the target driving force so as to maintain the target driving force. Subtract the difference between the target engine torque and the actual engine torque from the torque,
If there is a difference between the target engine torque and the actual torque of the engine and the operating state is the power generation torque priority state, the target power generation torque is maintained,
When there is a difference between the target engine torque and the actual engine torque, and when the operating state is the third priority state, the difference between the target engine torque and the actual engine torque, the target driving force, and the target power generation torque. A hybrid vehicle characterized in that the distribution of engine torque is set according to The hybrid vehicle according to claim 1, wherein the distribution of the engine torque is changed in stages for each determination of the priority state . 3. The hybrid vehicle according to claim 1, wherein the priority state determination unit determines the driving force priority state when a depression amount or a depression speed of an accelerator pedal is a predetermined value or more . The hybrid vehicle according to claim 3, 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 4, wherein the priority state determination unit determines the power generation torque priority state when a remaining battery capacity is equal to or less than a predetermined value . An engine that drives the vehicle;
In a hybrid vehicle having a function of generating electric power 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 the target driving force and the target power generation torque of the vehicle;
Torque distribution means for distributing engine torque to target driving force and target power generation torque;
Torque difference calculating means for calculating a difference between the calculated target engine torque and the actual engine torque;
Priority operating state determination means for determining an operating state to be prioritized according to the accelerator opening or the opening change rate and the SOC of the battery from the driving force priority state, the power generation torque priority state, and a third priority state other than these. And
When the difference between the target engine torque and the actual torque of the engine exists and when the driving state is the driving force priority state, the torque difference calculating means maintains the target driving force, Subtract the difference between the target engine torque and the actual engine torque from the target power generation torque,
If there is a difference between the target engine torque and the actual torque of the engine, and the operating state is the power generation torque priority state, the target power generation torque is maintained,
When there is a difference between the target engine torque and the actual engine torque and the operating state is the third priority state, the difference between the target engine torque and the actual engine torque, the target driving force, and the target power generation torque A control device for a hybrid vehicle, wherein distribution of engine torque is set according to

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