JP3332034B2 - Vehicle driving force control device and control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for controlling driving force of an automobile.

[0002]

2. Description of the Related Art Generally, the driving force of an automobile can be controlled by a combination of an engine and a transmission.

However, in the conventional apparatus, since the control of the engine and the transmission is individually performed, there is a serious problem in drivability.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 64-4544, attempts have been made to improve the drivability by increasing or decreasing the engine output during upshifting or downshifting of the transmission.

[0005]

However, even in such a proposal, in an actual vehicle, there is still an insufficiency between the drivability actually required by the driver and the actual drivability of the added vehicle. There was a problem that only a sense of agreement could be obtained.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a driving force control device and a control method for a vehicle, which provide a sufficient sense of agreement between the drivability required by the driver and the actual drivability of the vehicle to be added thereto. is there.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an engine
A method of controlling a vehicle equipped with an automatic transmission and an automatic transmission.
Depress the xel pedal to shift the automatic transmission.
Gear ratio of the automatic transmission.
With the throttle opening fully open.
Engine output increased, throttle opening fully open
Control the gear ratio to shift down and
The vehicle speed and access speed are controlled so that the throttle opening is controlled in the closing direction.
Gear ratio and engine torque based on the pedal depression amount
And obtain the engine torque and the rotation of the engine.
The throttle opening is obtained based on the number, and the engine and
This is achieved by controlling the automatic transmission.

[0008]

Embodiments of the present invention will be described below in detail.

FIG. 1 shows a power train system of an automobile, and its structure and operation will be described based on reference numerals.

The amount of depression of the accelerator pedal 1 is determined by the drive torque control means 2 and / or the engine torque control means 3
To enter. In the engine torque control means 3, a throttle controller 6 (motor, throttle valve, throttle sensor), a fuel injection device 7A, and an ignition device 7B provided in an intake pipe 5 attached to the engine 4 are controlled by the engine torque control means 3. Drive and control. The drive torque control means 2 drives the automatic transmission 30, the shift solenoid 8, the lock-up solenoid 9, and the like by proportional or duty control, and engages and disengages the shift clutch 10 and the clock-up clutch 11. Drive torque control is performed by combining this shift control with engine torque control.

The control of the shift position and the engine torque, particularly the drive torque control based on the combination of the throttle opening, is determined by the vehicle speed obtained from the signal from the rotation sensor 12 provided on the drive shaft and the depression amount of the accelerator pedal 1. In this embodiment, the engine torque control means 3 and the drive torque control means 2 are electrically connected and communicated via a local area network (LAN). Also, 32
When a high-performance computer such as a bit is used, it is possible to perform cooperative control of the engine and the transmission with a single control unit, such as the control unit 13 surrounded by a solid line.

FIG. 2 is a schematic diagram for basically explaining the control method of the present invention. The horizontal axis represents the vehicle speed, and the vertical axis represents the accelerator depression amount, that is, the driving torque. In FIG. 2, the solid line shows the driving torque when the throttle is fully opened, and the section [0-a] is 1
The speed region, the section [ab] is the second speed region, the section [bc] is the third speed region, and the section after [c →] is the fourth speed region. Next, as shown on the vertical axis, the target torque of the accelerator pedal depression amount is the driving torque and the vehicle speed [a] in the section of vehicle speed [0-a].
-B] section is driving torque, vehicle speed [bc] section is engine torque, and after vehicle speed c is engine torque. For example, in the vehicle speed [0-a] section, if the driver depresses the accelerator pedal to the value B, the target drive torque B corresponds to the accelerator depression amount. . In addition, when the vehicle speed is b or higher, the C-
Since the driving torque of D cannot be obtained, the target torque of the accelerator pedal depression amount needs to be the engine torque. Up to the vehicle speed [0-b] section, it is necessary to perform control using a combination of drive torque and engine torque.

FIGS. 3 to 5 are flowcharts for executing the control of FIG. In step (hereinafter referred to as S) 1, the accelerator pedal depression amount α, which is the required torque of the driver, is read, the engine speed Ne is read in S2, and the vehicle speed V is read in S3. Next, at S4, the vehicle speed V becomes a.
It is determined whether it is less than or equal to a.
-A], it is determined in step S5 whether the accelerator pedal depression amount α is equal to or less than A. S6 if A or less
To output a command signal for shifting the shift position to the fourth speed. At this time, the target value of the drive torque with respect to the accelerator pedal depression amount α is determined by searching a drive torque-accelerator depression amount map shown in FIG. Then, in step S7, the engine torque Te is obtained from the accelerator pedal depression amount α by using a function f in consideration of the deceleration ratio and the like. In step S8, the throttle opening θ shown in FIG.
th map using the th map, and finally S
In step 9, the throttle opening is output to drive the throttle controller 6, and the driving torque required by the driver is output.

Next, if the depression amount α of the accelerator pedal is smaller than A in S5, it is determined in S10 whether the depression amount α of the accelerator pedal is smaller than B, and if it is smaller than B, a third speed command is output in S11. In S12, the engine torque Te is determined in the same manner as in S7, and the process proceeds to S8.

Similarly, in step S10, the accelerator pedal depression amount α
Is equal to or greater than B, it is determined in S13 whether the value is equal to or less than C, and if it is equal to or less than C, a second speed command is output in S14, and S15
To determine the engine torque Te in the same manner as in S7, and then proceed to S8.

Further, if the accelerator depression amount α is equal to or more than C in S13, a first speed command is output in S16, the engine torque Te is obtained in S17 in the same manner as in S7, and the flow proceeds to S8.

The case where the accelerator depression amount α changes during the section [0-a] of the vehicle speed has been described above.

On the other hand, if the vehicle speed is equal to or higher than a in S4, the process proceeds to L shown in FIG. 4, and it is determined in S18 whether the vehicle speed is equal to or higher than b.

If the vehicle speed is determined to be in the [ab] section in S4 and S18, the accelerator depression amount α is set to A in S19 and S22.
Alternatively, it is determined whether or not the value of B is exceeded.

Thereafter, in S20 to S26, the same processing as in S6 to S17 and S8 and S9 in FIG. 3 is executed.

In this case, the first speed is not selected in the section of the vehicle speed [ab].

Next, when it is determined in S18 of FIG. 4 that the vehicle speed is higher than b, the process proceeds to M shown in FIG. 5, and in S27, it is determined whether the vehicle speed is higher than C.

If the vehicle speed is in the section [bc], it is determined in step S28 whether the accelerator depression amount is equal to or more than A, and thereafter, in steps S29 to S32, S8 and S9, the same processing as that shown in FIG. 3 is executed.

In this case, the first speed and the second speed are not selected in the vehicle speed [bc] section.

Finally, if it is determined in step S27 that the vehicle speed is equal to or higher than C, the flow directly advances to step S29 to issue a fourth speed command to obtain the throttle opening.

FIG. 8 is an iso-fuel efficiency rate diagram. While the horizontal axis represents the engine speed, the vertical axis represents the engine torque, and the broken line represents the engine torque when the throttle is fully opened. In FIG. 8, the shaded area is the area with the highest fuel efficiency.
Further, a solid line k indicates a best fuel consumption movement line until reaching the shaded portion. That is, the engine torque is increased while maintaining the engine speed at 1000 rpm, and
It is necessary to bring the engine torque close to the maximum while increasing the engine speed by about / 3. If the driving torque is controlled as in the present embodiment, the operating region passing on such a line of the best fuel consumption increases, so that the fuel economy is improved.

FIG. 9 is a characteristic diagram of the maximum drive torque with respect to the vehicle speed of the continuously variable transmission (CVT). As can be seen from the figure, when the continuously variable transmission is used, the gear ratio can be freely changed, so that there is no step in the drive torque.

The maximum value of the driving torque that changes according to the vehicle speed is set to the maximum value of the accelerator opening. That is, this becomes the target drive torque (accelerator opening) with respect to the vehicle speed.

For example, at the vehicle speed a, the driving torque of D becomes the maximum value of the accelerator opening, that is, the maximum target driving torque required by the driver. Then, when the accelerator opening and C, the gear ratio is changed from H ₁ to H _2, it remains fully open the throttle opening of the engine, it is possible to change the driving torque.

Further, when the accelerator opening in the vehicle speed b is A, and the gear ratio to H _4, the throttle opening is fully open.

FIG. 10 shows a control flowchart when the CVT is used. First, at S33 and S34, the vehicle speed (VS
P) and accelerator opening (α) are read, and FIG.
A map of the accelerator opening (target driving torque) with respect to the vehicle speed as shown in FIG. Then, the drive torque limit speed ratio H ₄ of the accelerator opening degree α is the high gear ratio side S36, that is, to determine whether greater than the target drive torque A, when large to fully open the throttle opening θ in S37,
In S38, a gear ratio that matches the vehicle speed and the accelerator opening is selected. On the other hand, if α <A, the engine torque Te is determined in S39.
= F (α) calculated throttle opening θ from the gear ratio in step S40 is the H ₄ limits.

As described above, in the present embodiment, a sense of coincidence between the drivability required by the driver and the actual drivability of the vehicle can be obtained.

Next, an application example of the present invention will be described.

FIG. 11 shows a control method of an application example. The relationship between the throttle opening and the driving torque differs depending on the shift speed as shown by the broken line. In the conventional control, when the accelerator pedal is depressed to gradually increase the driving torque as shown in FIG.
As shown by the solid line, the speed of the transmission was shifted down one after another. On the other hand, the method of the application example is shown in FIG.
When the driving torque is increased as in (b), the gear is maintained until the throttle is fully opened, and when a larger driving torque is required, the gear is shifted down. At this time, the operation of closing the throttle once so that the drive torque does not suddenly change, and further increasing the drive torque, fully opening the throttle again and further downshifting is repeated. As described with reference to FIG. 8, this system makes extensive use of the full throttle opening region and has a wide range in which the high gear stage is used, so that the engine speed can be kept low. Further, since the throttle opening is controlled so that the driving torque does not suddenly change during shifting, shock during shifting can be reduced.

FIG. 12 shows a control flowchart of the method shown in FIG. First, when a timer interrupt signal is input, the accelerator pedal depression angle and vehicle speed are measured in S50.
Next, in step S51, the driving torque and the shift speed are calculated from the accelerator pedal depression angle and the vehicle speed based on FIG. FIG. 13 shows the relationship between the vehicle speed, the driving torque, and the shift speed. The maximum driving torque with respect to the vehicle speed is shown by a solid line. The drive torque is calculated from the maximum drive torque corresponding to the vehicle speed and the accelerator pedal depression angle to determine the gear position. Here, since this method frequently uses the vicinity of the throttle fully open, there is a phenomenon that the gear is unstablely switched many times due to the noise of the accelerator pedal angle voltage and the like, and chattering occurs near the throttle fully open, and this is prevented. There is a need. Therefore, when shifting up,
In S52 and S53, the gear position is determined based on the broken line. By providing such hysteresis, chattering of gear shifting can be prevented, and wear of the transmission can be prevented.

Next, in S54, the engine torque is calculated from the product of the driving torque and the gear ratio. Next, a throttle opening signal and a shift signal are output in S56 for calculating the throttle opening by using a map of the throttle opening with respect to the engine speed and the engine torque created in advance in S55, and the engine output and the shift are changed. Control.

FIG. 14 shows another control method for performing the same speed change and throttle operation as the method shown in FIG. 11B. In this method, the shift and throttle control are performed with respect to the accelerator pedal depression angle and the throttle opening without considering the vehicle speed.

FIG. 15 shows a control flowchart for this.

In step S50, the accelerator pedal depression angle and the engine speed are measured. In step S57, when the engine speed exceeds the limit engine speed Maxrpm, the engine is worn out in step S5.
Shift up at 9. If the engine speed is equal to or less than Maxrpm, the gear position and the throttle opening are determined based on FIG. 14 in S58 and S60. Next, in step S61, a shift signal and a throttle opening signal are output to control shift and engine output.
This method is simpler than the method shown in FIG. 12, and has the advantage that the time required for calculation is short.

Next, FIG. 16 shows a processing flowchart in a case where the engine speed becomes excessive due to abnormal operation of the throttle and the transmission in the control method shown in FIG. In response to a timer interrupt, first, in step S62, the gear position and the engine speed are measured. If the engine speed is equal to or higher than the limit engine speed in S63, shift-up control is performed in S64 and S65, and the engine speed is reduced to prevent engine wear. In addition, it is also possible to notify the driver of an abnormality by using a warning light.

Next, application examples of the present invention will be described.

FIG. 17 shows a control block diagram at the time of deceleration. From the accelerator opening detecting means 31 and the brake pedal force detecting means 32, the deceleration determining means 33 determines whether the driver wants to decelerate. Thereafter, the deceleration determined by the driver is determined by the deceleration determining means 34. At this time, if the deceleration requested by the driver is the minimum, the shift position with the best fuel efficiency such as N (neutral) is directly output to the shift controller 35. If the deceleration requested by the driver exceeds a certain value, the speed ratio calculating means 36 outputs a speed ratio corresponding to the requested deceleration. Further, a throttle opening is obtained by a throttle opening calculating means 37 so as to prevent a shock at the time of shifting, and is output to a throttle controller 38.

FIG. 18 shows a control flowchart of FIG. First, in step S70, the accelerator opening α, the brake depression force β, the vehicle speed V, and the engine speed Ne are read. S71 to determine whether the vehicle speed V is greater than or equal _to V _0, the time of V ≧ V _0, S
At 72, it is determined whether or not the accelerator opening α is zero. When the accelerator opening α = 0, a flag (Flg) is set in S73 and S75, and in S74, during the arbitrary time xmsec, S7 is set.
In step 6, the current gear ratio inow is output. Next, xmsec in S74
At the moment, the flag (Flg) is cleared in S77, and the value of the brake depression force β is searched in S70. If the brake depression force β is smaller than β _{0 in} S78, the driver determines that the inertia deceleration is required, and sets the shift position to the neutral position (im = N) in S79. Next, when the brake depression force β is smaller than β ₁ in S80, the gear ratio i ₁ is obtained from the function (f) of the vehicle speed V and the engine speed Ne in S81. Then, S
Determined from a function of the transmission ratio i ₁ and the vehicle speed V (g) of the throttle opening degree θth at 82, and outputs the speed ratio i ₁ in the throttle opening θth and S83. Thereafter, similarly to the above control, the gear ratio and the throttle opening are obtained from the change in the brake pedal force. If the brake depression force β is the maximum βm in S84,
It is determined that the driver has requested the maximum braking force, and S8
5, S86, S87, so that the high engine speed
Find the gear ratio and throttle opening. Also, from βo to β
The m value is proportional to the controllable speed ratio of the automatic transmission.

FIG. 19 shows an outline of the overload reduction system. For example, in the case of a stepped automatic transmission, since a torque converter is used, an overload region exists as shown by a hatched portion in a first speed state in a low vehicle speed region. Therefore, as shown by the broken line, it is necessary to lower the maximum target value of the drive torque (the accelerator pedal fully opened). Thereby, the impact torque at the time of starting can be prevented. Also, if this method is used, the second drive, the third drive, the fourth drive,
Since many speed change positions can be used, fatigue applied to the drive system can also be reduced.

FIG. 20 shows a control block diagram of the overload reduction. The accelerator opening is detected by the accelerator opening detecting means 31 to determine whether or not overload control is necessary.
Judge by 0. If the above control is necessary, the throttle opening is obtained by the throttle opening calculating means 37, and then the corrected throttle opening is obtained by the drive torque correcting means 42 and output to the throttle controller. To the drive torque correction means,
The torque ratio of the torque converter is obtained and input by the torque ratio calculating means 41 and corrected.

FIG. 21 is a control flowchart of FIG. In S90, the accelerator opening α and the engine speed Ne are read. Then, when the accelerator opening degree α is ₁ or more α in S91, that is, at the vehicle speed V ₀ (30km / h etc.) or lower speed range, and if the shift position is the first speed, the transmission ratio i ₁ in S92 The target drive torque pressure is obtained by a function f of the accelerator opening α in S93. After that, the throttle opening θ is obtained from g (Tt, i ₁ , Ne) in S94 and output in S95. At this time, the maximum value of the driving torque is set to be the maximum value of the accelerator opening.

FIG. 22 shows a drive torque correction system based on a change in atmospheric pressure. In highlands (dashed lines) and lowlands (solid lines)
Since the atmospheric pressure changes, a difference occurs in the maximum driving torque. Therefore, in the case of high altitude, by using the speed ratio B 'at the vehicle speed a at the vehicle speed b, a driving torque similar to that of a flat ground can be obtained, and the driver's required driving torque due to a change in atmospheric pressure can be satisfied. It is.

FIG. 23 is a block diagram of the atmospheric pressure correction control. The atmospheric pressure is detected by the atmospheric pressure detecting means 43, and the corrected driving torque corresponding to the vehicle speed and the engine speed detected by the vehicle speed detecting means 44 and the engine speed detecting means 46 is obtained by the corrected driving torque calculating means 45. Thereafter, the corrected gear ratio calculating means 47 calculates the corrected gear ratio, and the corrected engine output calculating means 48 calculates the corrected throttle opening.
The output is sent to the shift controller 35 and the throttle controller 38.

FIG. 24 shows a control flowchart of FIG. At S100, the atmospheric pressure P, the vehicle speed V at S101, and the engine speed Ne at S102 are read. Then, in S103, the corrected drive torque ΔT ₀ is obtained from f (p, V).
At 104, the corrected speed ratio Δi is obtained from g (ΔT ₀ , Ne). Then, in S105, it is determined whether or not h (Δi, θ) obtained from the corrected gear ratio Δi and the throttle opening θ at that time is equal to ΔT ₀ . If they are the same, it is not necessary to correct the throttle opening, so the gear ratio Δi is directly output in S108. If they do not match in S105,
In S106, the corrected throttle opening Δθ is set to j (Δi, Ne).
The speed ratio Δi at that time is output from S107.
Output at 108.

FIG. 25 is a schematic diagram of the air-fuel ratio control. To improve fuel efficiency, the air-fuel ratio (A /
F) is made small and rich. In other regions, it is necessary to increase the air-fuel ratio (A / F) and make the air-fuel ratio lean.

FIG. 26 shows a flowchart of the air-fuel control. Speed ratio i in S110, vehicle speed V in S111, S112
Reads the throttle opening θ. Gear ratio i is determined whether the first speed i ₁ in S113, the vehicle speed V is V ₀ in S114
(Example: 60 km / h) if it is determined whether to determine whether the throttle opening theta is .theta.k or more S115, if i = i ₁ and V ≦ V ₀ cutlet a theta ≧ .theta.k, rich maps (A in S116 / F = 12), and in S117, the fuel amount Tp
Is output. In cases other than the above conditions, a lean map (A / F = 19) is searched in S118, and Tp is output in S117.

[0052]

As described above, according to the present invention, a sufficient sense of agreement can be obtained between the drivability required by the driver and the actual drivability of the vehicle following the drivability. In addition, the driver intends during lean operation
This gives a feeling of acceleration.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an automobile control device according to an embodiment of the present invention.

FIG. 2 is a diagram schematically illustrating control of a vehicle control device according to an embodiment of the present invention.

FIG. 3 is a flowchart for executing the control of FIG. 2;

FIG. 4 is a flowchart for executing the control of FIG. 2;

FIG. 5 is a flowchart for executing the control of FIG. 2;

FIG. 6 is a diagram showing a correspondence between an accelerator and a torque.

FIG. 7 is a throttle opening map corresponding to rotation speed and torque.

FIG. 8 is a fuel consumption characteristic diagram corresponding to the rotation speed and the torque.

FIG. 9 is a diagram schematically illustrating another control using the continuously variable transmission.

FIG. 10 is a control flowchart of FIG. 9;

FIG. 11 is a characteristic diagram for explaining another application example of the present invention.

FIG. 12 is a flowchart for implementing the characteristics of FIG. 11;

FIG. 13 is a characteristic diagram of vehicle speed-drive torque-shift position.

FIG. 14 is a characteristic diagram for explaining another application example of FIG. 11;

FIG. 15 is a flowchart for implementing the characteristics of FIG.

FIG. 16 is a flowchart of an abnormality countermeasure corresponding to the flowchart shown in FIG. 12;

FIG. 17 is a configuration diagram of another application example of the present invention.

18 is a flowchart of the application example shown in FIG.

FIG. 19 is a characteristic diagram of another application example of the present invention.

FIG. 20 is a configuration diagram for implementing the characteristics of FIG. 19;

FIG. 21 is a flowchart of the application example shown in FIG. 19;

FIG. 22 is a characteristic diagram of another application example of the present invention.

FIG. 23 is a configuration diagram for implementing the characteristics of FIG. 22;

FIG. 24 is a flowchart of the application example shown in FIG. 22;

FIG. 25 is a characteristic diagram of another application example of the present invention.

FIG. 26 is a flowchart for implementing the characteristics of FIG. 25;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Accelerator pedal, 2 ... Drive torque control means, 3 ... Engine torque control means, 4 ... Engine, 6 ... Throttle controller, 7A ... Fuel injection device, 7B ... Ignition device, 8 ... Shift solenoid, 10 ... Shift clutch, 30 ... automatic transmission.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI F02D 41/04 310 F02D 41/04 310G (72) Inventor Yutaka Nishimura 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Hitachi Research Laboratory Examiner Hiroshi Hayashi (56) References JP-A-1-141133 (JP, A) JP-A-63-195456 (JP, A) JP-A-63-2739 (JP, A) JP-A-57-140534 (JP) JP-A-61-38253 (JP, A) JP-A-62-110536 (JP, A) JP-A-62-110535 (JP, A) JP-A-61-119856 (JP, A) 58-160661 (JP, A) JP-A-58-191357 (JP, A) JP-A-62-244727 (JP, A) JP-A-63-105525 (JP, A) JP-B-51-18574 (JP, A) B1) (58) Field surveyed (Int. Cl. ⁷ , DB name) B60K 41/00-41/28 F02D 3/00 -45/00

Claims (6)

(57) [Claims] 1. A method for controlling an automobile equipped with an engine and an automatic transmission, wherein when an accelerator pedal is depressed to shift down the automatic transmission, the speed ratio of the automatic transmission is maintained. The engine speed is increased until the throttle opening is fully opened, and after the throttle opening is fully opened, the vehicle speed and the gear ratio are controlled to shift down and the throttle opening is controlled in the closing direction. The transmission ratio and the engine torque are obtained based on an accelerator pedal depression amount, a throttle opening is obtained based on the engine torque and the engine speed, and the engine and the automatic transmission are controlled. Car control method. 2. The automatic transmission according to claim 1, wherein a speed stage of the automatic transmission is a second speed, a third speed, or a fourth speed, the vehicle speed is 60 km / h or more, and the throttle opening is A method for controlling a vehicle, wherein the air-fuel ratio is controlled to be lean when the value is equal to or more than a predetermined value. 3. The automatic transmission according to claim 1, wherein the shift stage of the automatic transmission is a first speed, the vehicle speed is 60 km / h or less, and the throttle opening is a predetermined value or less. A method for controlling an automobile, wherein the air-fuel ratio is controlled to be rich. 4. A control system for an automobile having an engine and an automatic transmission, the control system for an automobile shifting down the automatic transmission when an accelerator pedal is depressed. The engine output is increased until the throttle opening is fully opened while maintaining the gear ratio, and after the throttle opening is fully opened, the gear ratio is controlled to shift down and the throttle opening is controlled in the closing direction. The speed ratio and the engine torque based on the vehicle speed and the accelerator pedal depression amount, the throttle opening based on the engine torque and the engine speed, and the throttle opening controlled. Outputting a throttle opening signal and a shift signal for controlling a shift of the automatic transmission. Your system. 5. The method of claim 4, gear position the second speed of the automatic transmission, a third speed or fourth speed, and the vehicle speed is not more 60 km / h or more, and, the throttle opening A control system for an automobile, wherein the air-fuel ratio is controlled to be lean when the value is equal to or more than a predetermined value. 6. The method of claim 4, a gear is first gear of the automatic transmission, and the vehicle speed is equal to or lower than 60 km / h, and, when the throttle opening is less than a predetermined value Is a vehicle control system characterized by richly controlling the air-fuel ratio.