JP3316867B2 - Vehicle torque control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle torque control apparatus for controlling a motor that drives a vehicle to control the output torque of the vehicle, and more particularly to a vehicle torque control apparatus that prevents hunting during acceleration and improves acceleration. The present invention relates to a torque control device.

[0002]

2. Description of the Related Art Since a vehicle constitutes a kind of vibration system by a suspension or the like, during rapid acceleration, acceleration hunts as shown by a dotted line in FIG. Therefore, the inventor of the present invention estimates an estimated torque required for a vehicular internal combustion engine based on an accelerator operation amount and an engine operating state, as described in JP-A-3-78542, and calculates the estimated torque
The throttle valve is controlled based on the target torque obtained by correcting the estimated torque in such a manner that hunting of the vehicle acceleration is corrected in accordance with the values of operating variables related to the vehicle's vibration system, such as the gear position and suspension hardness. A control device for an internal combustion engine for vehicles is proposed.

[0003] In this type of vehicle internal combustion engine control device,
By correcting the estimated torque, vibration applied to the vehicle during acceleration or the like can be almost completely canceled as shown by the dashed line in FIG. Therefore, the driver can experience a very smooth feeling of acceleration.

[0004]

However, in this type of control device for a vehicle internal combustion engine, hunting of vehicle acceleration is almost completely prevented, and so-called overshoot in which the acceleration exceeds a target value is also eliminated. For this reason, although the actual acceleration is not deteriorated, the feeling of acceleration experienced by the driver is reduced. It is also desired to further improve the acceleration of the vehicle.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a torque control device for a vehicle that allows the driver to fully experience the feeling of acceleration and to improve the acceleration of the vehicle.

[0006]

SUMMARY OF THE INVENTION The present invention, which has been made to achieve the above object, comprises a prime mover for driving a vehicle, an accelerator operation amount detecting means for detecting an accelerator operation amount, as shown in FIG. An engine operating state detecting means for detecting an operating state of the prime mover, a vehicle operating variable detecting means for detecting a value of an operating variable relating to a vibration system of the vehicle, an accelerator operation amount detecting means and an engine operating state detecting means. A torque estimating means for estimating a torque required for the prime mover based on the detection result; anda torque estimating means for estimating the torque estimated by the torque estimating means. Torque correcting means for correcting, and a motor control means for controlling the motor based on a target torque obtained by correcting the estimated torque by the torque correcting means, In the torque control device for a vehicle with, based on the detected operating state by said engine operating condition detecting means, the estimated torque as the desired acceleration feeling is obtained, so as to converge overshot once A gist of the invention is a torque control device for a vehicle, comprising: an estimated torque correcting means for correcting, wherein the estimated torque corrected by the estimated torque correcting means is corrected by the torque correcting means.

[0007]

The present invention constructed as described above operates as follows. First, the torque estimating means estimates the torque required of the prime mover based on the accelerator operation amount detected by the accelerator operation amount detecting means and the operating state of the prime mover detected by the engine operating state detecting means. Subsequently, the estimated torque correcting means overshoots the estimated torque estimated by the torque estimating means only once based on the operating state detected by the engine operating state detecting means so as to obtain a desired acceleration feeling. And correct it so that it converges. Further, the torque correcting means corrects the corrected estimated torque in a direction for preventing hunting of the vehicle acceleration based on the value of the driving variable relating to the vibration system of the vehicle detected by the vehicle driving variable detecting means. Then, the prime mover control means controls the prime mover based on the target torque obtained by correcting the estimated torque in this way.

[0008] By controlling the prime mover for driving the vehicle in this way, a desired acceleration feeling can be obtained.
After only overshoot once so that it is possible to converge to a predetermined value corresponding to the accelerator operation amount without causing hunting. The estimated torque correcting means sets a target value of the overshoot rate based on the operating state detected by the engine operating state detecting means, and calculates the estimated torque based on the target value. It may be corrected. In addition, the estimated torque correction means may determine the overshoot rate based on the accelerator operation amount detected by the accelerator operation amount detection means and the operating state detected by the engine operation state detection means. A target value may be set, and the estimated torque may be corrected based on the target value.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 2 is a schematic configuration diagram illustrating a vehicle torque control device of the embodiment applied to the internal combustion engine 1 for a vehicle. An internal combustion engine (hereinafter simply referred to as an engine) 1 is a spark ignition type four-cylinder gasoline engine, and is mounted on a vehicle. An intake pipe 3 and an exhaust pipe 5 are connected to the engine 1. The intake pipe 3 is a collecting part 3 connected to an air cleaner (not shown).
a and a surge tank 3b connected to the collecting portion 3a
And a branch portion 3c branched from the surge tank 3b corresponding to each cylinder of the engine 1.

The output (torque) generated in the engine 1 by controlling the amount of air taken into the engine 1 is provided to the collecting portion 3a.
Is provided with a throttle valve 7 for controlling the pressure. The valve shaft of the throttle valve 7 has a step motor 9 for adjusting the opening of the throttle valve 7 and the opening θa of the throttle valve 7.
And a throttle sensor 11 for generating a voltage signal proportional thereto.

The step motor 9 is provided with a motor fully closed sensor 9a for detecting a fully closed position of the motor 9. Further, an intake air temperature sensor 13 for detecting an intake air temperature is provided at a position upstream of the throttle valve 7 in the collecting section 3a.

The surge tank 3b is provided with an intake pipe pressure sensor 14 for detecting the pressure Pm in the intake pipe 3 adjusted by the throttle valve 7. Each branch 3c has a fuel in the branch 3c. Are provided respectively. The engine 1 also has a spark plug 17 for igniting the air-fuel mixture taken in for each cylinder.
Is provided. The spark plug 17 is connected to a distributor 19 via a high-pressure cord, and the distributor 19 is electrically connected to an igniter 21. A rotation sensor 1 for outputting a signal synchronized with the engine rotation is provided to the distributor 19.
9a is provided.

Further, the engine 1 is provided with a water temperature sensor 23 for detecting a temperature TH of cooling water for cooling the engine 1. Then, the engine speed Ne is detected by the signal of the rotation sensor 19a, and the basic amount of the fuel injection amount is calculated based on the engine speed Ne, the intake pipe pressure Pm, the water temperature TH, and the like.

The torque of the engine 1 is determined by the opening of the throttle valve 7. The torque generated by the engine 1 is transmitted to the right rear wheel 31 and the left rear wheel 33 forming driving wheels via the clutch 25, the transmission 27, the differential gear 29, and the like.
Conveyed to. The transmission 27 has a gear position sensor 2 for outputting a gear position signal corresponding to the gear position.
7a, a right rear wheel 31, a left rear wheel 33
In addition, the right front wheel 35 and the left front wheel 37, which form driven wheels, are provided with wheel speed sensors 31a, 33a, 35a, 37a for detecting wheel rotation speeds, which are parameters required for traction control and auto-cruise control, respectively. .

A steering angle sensor 3 is provided on the shaft of the steering wheel 39.
9a is provided to detect a steering angle SA of the front wheels 35 and 37 that changes with the operation of the steering 39. An air-fuel ratio sensor 62 is attached to the exhaust pipe 5 to detect an air-fuel ratio (A / F).

A G sensor 63 for detecting vehicle acceleration (vehicle G) in the front-rear direction is attached to a lower portion of the rear seat dashboard. Suspensions 60a, 60b, 60c, 6 are provided between the wheels 31 to 37 and a vehicle body (not shown).
0d is provided. Each suspension 60a-60
In the case of c, the hydraulic pressure of the suspension is controlled by the hydraulic control device 61 for the suspension, and the damper characteristic (damping force of the shock absorber) can be controlled. The left front wheel suspension 60b has a suspension deflection (stroke) sensor 6 for detecting the amount of deflection of the suspension.
4 is attached. The load on the vehicle can be estimated from the amount of deflection of the suspension detected by the stroke sensor 64.

The left driven wheel 37 is provided with a tire pressure sensor 65 for detecting the tire pressure. The brake oil pressure of the rear wheel brakes 66a and 66b can be controlled by the brake oil pressure control device 67.

A mechanical supercharger 68 is provided in the intake pipe 3. In a passage 71 bypassing the supercharger 68, there is a waste pressure valve 70 for controlling a supercharging pressure. The valve 70 is controlled by a step motor 69.
An exhaust pressure control valve 72 provided in the exhaust pipe 5 is driven by a step motor 73 to control the exhaust pressure.

A passage 74 constituting an exhaust gas recirculation (EGR) system is provided between the intake pipe 3 and the exhaust pipe 5.
The valve 75 for controlling the EGR amount is driven by a step motor 76. The recirculated exhaust gas flows from the exhaust pipe 5 through the passage 74 to the downstream portion of the throttle valve 7.

In the vicinity of each cylinder of the engine 1, a variable valve timing device (VVT) 77 for controlling the valve timing and lift of an intake / exhaust valve (not shown).
Is provided. Regarding VVT, see JP-A-64-3
No. 214 is known.

An accelerator operation amount sensor 41a for outputting a signal Ap corresponding to the operation amount of each sensor and the accelerator pedal 41, and an accelerator for detecting that the accelerator pedal 41 is released and the accelerator is fully closed. The signals of the fully-closed sensor 41b, the brake sensor 43a that is turned on when the brake pedal 43 is depressed, and the clutch sensor 42a that is turned on when the clutch pedal 42 is depressed are input to an electronic control unit (ECU) 50,
The CU 50 outputs a signal for driving the step motor 9 of the throttle valve, the injection valve 15, the igniter 21, and other control devices 69, 61, 67, 73, 76, 77 based on these signals. The ECU 50 includes a CPU, R
It is configured as a well-known electronic control circuit mainly including OM, RAM, and the like.

The driver's seat is provided with an auto cruise switch 81 and a sports mode switch 82.
The auto cruise switch 81 is a switch that is turned on by the driver when performing auto cruise control. On the other hand, the sports mode switch 82 is a switch that is turned on when the driver particularly wants to select sporty running with a sharp rise at the time of acceleration.
This makes it possible to change the start-up characteristic during acceleration of control of the throttle valve 7 described later.

Next, in the above-described apparatus, a process until the operation amount of the accelerator pedal operated by the driver is converted into the opening degree of the throttle valve 7 will be described in detail. First, FIG. 3 is a flowchart showing a main routine of vehicle torque control executed by the ECU 50 of the present embodiment. This routine is executed every predetermined time. When the process is started, first, in step 1010, an engine operation state such as an accelerator operation amount Ap by a driver, an engine speed Ne, and a wheel speed is read. Then, in the next step 1020, a torque required for the engine 1 is estimated from the accelerator operation amount Ap and the engine speed Ne, and this is calculated as an estimated torque serving as a source of a parameter for driving the throttle valve 7. The next step 1030 is a step of determining whether or not a condition for correcting the estimated torque and calculating a target torque described later is satisfied.

If an affirmative determination is made in step 1030, the process proceeds to step 1040. In step 1040, an overshoot ratio represented by the ratio of the maximum torque to the estimated torque is calculated. In the following step 1050, a first-order advance filter described later is set based on the overshoot rate, and in step 1060, the estimated torque is converted by the first-order advance filter. Next, in step 1070, the target torque is calculated by correcting the converted estimated torque based on the value of the driving variable relating to the vibration system of the vehicle so that hunting of the vehicle acceleration is prevented. In the following step 1080, the target opening of the throttle valve 7 is calculated based on the target torque. Finally, in step 1090, a drive signal is output to the step motor 9, and the throttle valve 7 is driven so as to have the target opening degree, and the processing is terminated.

On the other hand, if a negative determination is made in step 1030, the process proceeds to step 1100. In step 1100, the target throttle opening is directly calculated based on the estimated torque obtained in step 1020. Subsequently, the flow shifts to step 1090, where the throttle valve 7 is driven as described above to end the processing.

Hereinafter, each processing of the flowchart of FIG. 3 will be described in more detail. First, in step 1020,
Engine torque (estimated torque) TT requested by driver
Is estimated from the operation amount Ap of the accelerator pedal 41 by the driver and the engine speed Ne at that time based on the map of FIG. FIG. 5 shows a map having the same shape as that obtained by inverting the map of FIG. Conventionally, this estimated torque T
Since the target throttle opening θ is determined by inverting T as it is using the map of FIG. 5, when the driver performs a rapid acceleration operation of the accelerator as shown by a dotted line in FIG. The acceleration G in the front-rear direction of the vehicle largely hunted back and forth, and the riding comfort was poor. Therefore, in this example, hunting is prevented by correcting the estimated torque TT in steps 1040 to 1070 described later.

It is desirable that the estimated torque is further corrected based on whether the supercharger is operating with respect to the map shown in FIG. That is, the estimated torque TT is set higher during the operation of the supercharger. Similarly, for the VVT 77 and the intake / exhaust control device (not shown), as the torque increases, the T
Set T to a higher value. In addition, atmospheric pressure Pa, water temperature T
Since the engine torque differs depending on H, it is better to correct TT using the maps of FIGS. 6 and 7 and the following equation. That is, TT · Kw · Ka obtained by multiplying the TT obtained in FIG. 4 by the correction coefficients Ka and Kw may be used as the new estimated torque TT.

The estimated torque TT is not the torque itself but an equivalent parameter such as the intake pipe pressure Pm or, in a system having an air flow meter, the intake air amount Qe / Ne per revolution of the engine. Is also good. In calculating the estimated torque TT,
Instead of relying on the map of FIG. 3, it may be obtained from the following formula.

[0029]

(Equation 1)

K1 to K5: Positive constant Note that in a vehicle with a supercharged engine, the larger the supercharge amount, the larger the value of K
1, K2 may be increased. Next, the conditions determined in step 1030 of FIG. 3 will be described with reference to FIG.

Step 4001: As described above, the pedal operation amount of the driver may fluctuate due to the front-rear vibration of the vehicle due to road surface disturbance. The determination of the steady running is performed according to the process shown in the flowchart of FIG.

Here, the flowchart of FIG. 30 will be described in detail. FIG. 31 shows how the flowchart of FIG. 30 is executed. That is, in FIG.
The change amount Ap 'of the accelerator operation amount per a predetermined time is calculated from the accelerator operation amount Ap detected in step (1) and the previous value of Ap. In the next step 7001, | Ap '| ≧ predetermined value A
When p0 (Ap0> 0), it is determined that acceleration has started, and the routine proceeds to step 7003. Step 1040 in step 7003
Is set to ON, and in the next step 7004, the counter CF is set (CF = 0).

At step 7001, it is determined that | Ap '| <Ap0, and at step 7002, the execution flag XF = O
In the case of FF, it is determined that the vehicle is in a steady state in which hunting does not occur or in a gentle acceleration state, and does not require the torque correction by the processing in step 1040 and thereafter.
Leave OFF. | Ap '| <Ap0 and XF = O
In the case of N, since there is a possibility that the vehicle is still accelerating, the process proceeds to step 7005 to determine whether or not the vehicle is accelerating. In step 7005, it is determined that the vehicle is accelerating for a predetermined time T0 (for example, 0.5S) after the accelerator is operated at the speed of | Ap '| ≥Ap0, and that it is not accelerating when the predetermined time T0 has already elapsed. . That is, in step 7005, the counter CXF is compared with KCXF corresponding to T0,
If F ≧ KCXF, the routine proceeds to step 7006, where it is determined that acceleration is not being performed, and XF = OFF. Then, the counter is updated (incremented) in step 7007.

If it is determined whether or not the vehicle is traveling in a steady state according to the procedure shown in FIG. 30 and if the routine is not executed during the steady traveling, it is assumed that | Ap '| instantaneously becomes a large value due to the influence of road surface disturbance during acceleration. An erroneous determination can be prevented. Step 4002: If the friction coefficient μ of the road surface is smaller than the predetermined value μ0, it is determined that the condition is not satisfied.

It is dangerous to open the throttle during deceleration even though there is no pedal operation. μ is detected by
Intake temperature ≤ using intake (atmospheric) temperature by intake temperature sensor
When the value is a predetermined value, it may be determined that μ is small. Alternatively, μ <μ0 may be used instead of the acceleration of the driving wheel when the driving wheel slips, that is, when the acceleration of the driving wheel when slipping is larger than a predetermined value.

Step 4003: If the road surface unevenness is larger than a predetermined value (for example, a gravel road), step 104 in FIG.
Since the execution of the processing of 0 or less may increase the vibration, the condition is not satisfied. This is because the overshoot of the throttle valve in the TF → θ conversion block executed in step 1080 of FIG. 3 impairs the steady state vehicle stability when the pedal moves synchronously due to road surface disturbance (unevenness). Because there is. The road surface unevenness is determined by the vehicle G using the G sensor. When the vehicle G is hunting at a high frequency, the magnitude of the hunting amplitude is defined as the size of the unevenness.

Step 4004: Auto-cruise automatic low-speed running control) During control (auto-cruise switch 81 is set to O
N) assumes that the condition is not satisfied. This is because Ap = 0. Step 4005: The condition is not satisfied even when the traction is executed. This is because it is necessary to prioritize slip suppression.

Step 4006: The condition is not satisfied in order to preferentially perform the fail process even when the pedal sensor, the throttle body, etc. fail. Step 4007: Normally, since the engine torque changes according to the A / F (air-fuel ratio), the estimated torque TT is determined by performing a correction according to the A / F, or when the engine is lean, simply increase the fuel or perform asynchronous injection. , It is preferable to perform weight reduction correction when rich. However, if 10 ≦ A / F ≦
If it is not at 20, the estimated torque TT may not be as shown in FIG. 4. Therefore, this step is inserted to prevent the A / F from reaching a predetermined If it is out of the range, the condition is not satisfied.

Step 4008: As described above, although the estimated torque TT corresponding to the engine temperature has already been determined, this step is inserted to make the cooling water temperature TH ≦ the predetermined value TH0.
In this case, since the actual torque may vary, the condition may not be satisfied. Step 4009: If no load is applied irrelevant to vehicle vibration, it is not established. No load is detected by crash sensor 42
a from ON / OFF and the gear position signal from the gear position sensor 27a. That is, it is determined that there is no load when the clutch is depressed (clutch sensor ON) and when the gear position signal is in the neutral state.

Step 4010: It is determined that the brake operation is not established. It is dangerous if the throttle valve 7 is opened by the deceleration control. The brake operation is detected by the brake sensor 43a.
Do with. Step 4011: It is considered that the condition in the torque correction condition determination switch 1030 of FIG. 3 is satisfied. This causes the process to proceed to step 1040 in FIG.

Step 4012: It is considered that the torque correction condition is not satisfied. This causes the process to proceed to step 1070 in FIG. In the normal control step 1070, the target opening θ of the throttle valve is obtained from the accelerator operation amount Ap and the rotation speed Ne from the map of FIG. Note that θ is the traction target opening during traction control, and is the aforementioned cruise target opening θc during auto cruise control.

Next, the processing for calculating the target torque TF from the estimated torque TT executed in steps 1040 to 1070 will be sequentially described. As described above, the overshoot rate is represented by the ratio (B / A) of the maximum torque B to the estimated torque TT (the magnitude is A) (see FIG. 33). In step 1040, the overshoot ratio B / A is obtained from the map shown in FIG. 12 based on the accelerator operation amount Ap and the engine speed Ne.

Here, the map of FIG. 12 is set as follows. That is, there is a correspondence relationship between the output torque of the engine 1 and the accelerator operation amount Ap as shown in FIG. The output torque increases as the accelerator operation amount Ap increases. When the accelerator operation amount Ap is further increased, the output torque converges to a predetermined value corresponding to the engine speed Ne. Accelerator operation amount Ap at which the output torque with respect to the predetermined value is less than 50% (a range where Ap <Apl when the engine speed is 2000 rpm)
Then, the overshoot ratio B / A is set to 2. Similarly,
In a range where the output torque is 50% or more and less than 67% of the predetermined value (Apl ≦ Ap <Aph), B / A = 1.5, and a range where the output torque is 67% or more of the predetermined value (Aph).
</ Ap), B / A = 1.0. By performing such a setting for all engine speeds, FIG.
2 maps can be set.

If it is desired to improve the sense of acceleration by expanding the region in which the overshoot is made, the accelerator operation amount Ap is converted into a corrected accelerator operation amount App by a non-linear function as shown in FIG. The overshoot rate may be calculated using the twelve maps.

In the following step 1050, step 10
Based on the overshoot ratio B / A calculated at 40,

[0046]

(Equation 2)

T0: Sets a first-order advance filter expressed by a transfer function of a predetermined time. FIG. 15 shows a Bode diagram of the primary advance filter. With such a first-order filter, FIG.
When the step-like waveform illustrated in (a) is converted, FIG.
As shown in FIG. 6B, a waveform is obtained which once overshoots to the predetermined value B and then gradually decreases and converges to the predetermined value A. The convergence of the waveform to the predetermined value A is almost after the time T0.

In the following step 1060, step 10
The estimated torque TT obtained at step 20 is converted by the above-mentioned first-order advance filter. As a result, when the accelerator operation amount Ap sharply increases, the converted estimated torque TT (hereinafter referred to as the overshoot estimated torque Tp) becomes the estimated torque T
After once overshooting at B / A times T, it converges to the estimated torque TT at about time T0.

Next, the estimated overshoot torque T
Step 1070 in FIG. 3 for converting p into target torque TF
A first example will be described. As described above, when the torque changes stepwise, the vehicle generates hunting as shown by the dotted line in FIG.

The occurrence of the hunting is caused by the fact that the torque and the acceleration in the longitudinal direction of the vehicle (vehicle G) are a secondary spring-mass system by the suspension. When the vehicle G is represented by a transfer function,

[0051]

(Equation 3)

Ωn: frequency, Aξ: attenuation rate, and the frequency characteristics are as shown in FIG. The amplification of the natural frequency f0 component in FIG. 17 causes hunting. Aξ is the amount of attenuation, and hunting is more likely to occur as the value is larger.

Hunting can be prevented by applying a filter having an inverse characteristic of the frequency characteristic shown in FIG. 17, that is, a filter having the characteristic shown in FIG. 18 to the estimated overshoot torque Tp. That is, due to the filter characteristics shown in FIG.
And the amount of attenuation Aξ can be reduced.

Further, in this embodiment, the vehicle stability can be improved even when the responsiveness of the throttle actuator is changed, or when the vehicle moves in the front-rear direction in synchronization with the road surface disturbance, the pedal operation amount of the driver fluctuates. In order to compensate for the characteristic, a filter having the characteristic shown in FIG. 19, which attenuates in the high frequency region f1 or higher, is combined in series with the filter shown in FIG. Therefore, finally, a filter having a characteristic as shown in FIG. 20 is generated, and the estimated overshoot torque Tp is generated.
Is applied.

The natural frequency f0 and the attenuation signal of the filter shown in FIG. 20 are expressed as follows.

[0056]

(Equation 4)

Δ: damping ratio, k: vehicle spring constant, M: weight, G: damper characteristics Here, the spring constant k changes with the suspension hardness (in the case of an air damper). The weight M is determined by the sum of the vehicle weight and the inertial mass when the drive system is viewed from the wheel side. This inertial mass changes depending on the gear ratio. In other words, the inertia mass of the drive system with respect to the wheel side increases as the gear ratio increases.

The damper characteristic G changes depending on the suspension hardness and the tire pressure. From the above, it can be seen that the filter characteristics may be changed according to the values of the operating variables such as the gear position (gear position), the hardness of the suspension, the vehicle mass, and the tire pressure. Next, a procedure for filtering the converted overshoot estimated torque Tp in step 1070 will be described with reference to the flowcharts of FIGS. As shown in FIG. 21, the filtering mainly includes two routines. Step 100 is a routine for setting the filter characteristics in FIG. 20, and step 200 is a routine for actually calculating the set filter characteristics.

FIG. 22 shows a filter characteristic setting routine of step 100. In steps 101 and 102, it is specified whether or not the engine is in a no-load state. If the characteristic is switched to the characteristic shown in FIG. 20 at the time of load operation such as acceleration, a vehicle shock may be caused. Therefore, when the clutch sensor 42a is ON or the transmission 27 is in the neutral state, such as when shifting or when the vehicle is stopped. Switching is performed only when there is no load. If there is no load, the routine proceeds to step 103, where the natural frequency f0 is set according to the gear position, suspension hardness (in the case of an air damper), and vehicle mass. Since hunting occurs only in the frequency range above the frequency f0, the estimated overshoot torque Tp may be attenuated in this hunting range. Now, f0
= F0 '· kf1 · f2 (f0': fundamental natural frequency, k
f1 is a correction coefficient of f0 determined from vehicle mass, and kf2 is a correction coefficient of f0 determined by suspension hardness. F0 ', kf1, and kf2 are respectively shown in FIG.
(B) and (c) are set. In other words, the lower the gear, the larger the vehicle mass, or the softer the hardness of the suspension, the smaller the natural frequency f0 is set.

Next, the routine proceeds to step 104, where an attenuation signal is set. The damping rate ξ is a specific basic damping signal ξ ′ determined in advance by the elasticity of the vehicle underbody system (suspension, damper, etc.).
This basic damping rate ξ ′ is shown in FIGS. 25 (a), (b) and (c) according to the values of driving variables such as tire pressure, suspension hardness and vehicle mass. The correction is performed using the correction coefficient. The decay rate ξ is ξ = ξ ′ · k
It is calculated by the following equation: ξ1 · kξ2 · kξ3 (kξ1: correction coefficient of ξ determined by tire pressure, kξ2: correction coefficient of ξ determined by suspension hardness, kξ3: correction coefficient of 定 determined by vehicle mass). In other words, the smaller the tire pressure,
Alternatively, the softer the suspension and the lighter the vehicle mass, that is, the smaller the load, the smaller the attenuation signal ξ 'is set. Note that the smaller the attenuation rate ξ, the more the attenuation amount A
ξ increases.

Next, the process proceeds to step 105, where
One of the nine types of filter characteristics Fi (i = 1,..., 9) is selected from the map shown in FIG. 26 according to the natural frequency f0 and the damping rate ξ obtained in steps 03 and 104. Each filter characteristic Fi defines five coefficients KF0 to KF4 for performing a filtering calculation described below, and Fi is stored in the ROM 50d in advance.

According to the routine of FIG. 22, the execution of the setting change of the filter characteristic is prohibited when there is a load. Thus, the filter characteristic setting routine 100 of FIG. 21 ends. FIG. 23 shows the filtering calculation routine 2 of FIG.
The detailed procedure for 00 is shown. The filtering calculation is performed based on the value of the estimated overshoot torque Tp up to two times before and the value of the filter characteristic coefficient obtained in step 105 of FIG. Step 201
Then, the previous value of the input estimated overshoot torque Tp is updated and the current Tp is taken in. Step 2
Numeral 03 is for updating the previous value of the output target torque TF.

Then, the estimated overshoot torque Tp
Is converted to the target torque TF in step 202. That is, TF = KF0Tp0 + KF1Tp1 + KF2Tp2 + KF3TF1 + KF4TF2. The coefficients KF0 to KF4 are values set in the filter characteristic setting step of step 105.

By this filtering calculation, the specific frequency component of the estimated overshoot torque Tp to be input is attenuated at the attenuation rate ス ロ ッ ト ル. If the throttle control is executed with the attenuated output TF as the target torque, the hunting of the vehicle G will occur. It is possible to converge by overshooting only once without waking up.

As described above, this embodiment includes a filter having the characteristic shown in FIG. 19, which attenuates in the high frequency region f1 or higher. When f1 is reduced, the vehicle G rises more slowly, and when f1 is increased, the rise becomes steeper. Therefore,
By changing f1, it is possible to freely select a sporty ride with a sharp rise or a relaxed ride with a luxurious feeling, although the rise is somewhat reduced. This is the sport mode switch 8 at hand
Switching is possible by the operation 2.

Further, in order to prevent sudden acceleration on a slippery road surface, a friction coefficient μ of the road surface is detected, and FIG.
F1 may be set as follows. As is clear from the characteristics of FIG. 26, it is preferable that the larger the value of μ, the larger the band of f1. In addition, as shown in FIG. 27, the characteristics may be switched so that f1 becomes smaller on a rough road surface having a large unevenness, as shown in FIG. 27, so that slow acceleration and rapid acceleration can be automatically selected. The detection of environmental variables such as the friction coefficient μ of the road surface or the unevenness of the road surface will be described later.

Since the natural frequency f0 (hunting frequency) changes due to environmental changes or changes over time or characteristics of the engine or the vehicle, better controllability can be realized by learning. As a learning method, the above-described longitudinal acceleration G of the vehicle may be detected by a G sensor, a hunting cycle may be calculated, and reflected in f0. FIG. 28 is a flowchart showing a process of calculating the hunting cycle. In step 6000, the detected vehicle G
The hunting amplitude AG is calculated from the above, and it is determined whether or not AG is equal to or larger than a predetermined value (whether or not hunting is performed). A
When G ≧ predetermined value, the process proceeds to step 6001, and the hunting periods T1, T2, and T3 of the past three times are calculated. Hunting periods T1, T2, T calculated in step 6002
3 is calculated, and f0 is calculated from TH (f0
= 1 / TH).

When the target torque TF is determined as a result of correcting the estimated torque TT in Steps 1040 to 1070, the target throttle opening θ is calculated in Step 1080 based on the target torque TF. What is necessary is to drive the throttle valve 7 to the opening degree θ.

However, if the target torque TF is converted to the throttle opening using the map of FIG. 5 as it is, the vehicle acceleration cannot be overshot only once, and hunting of the vehicle acceleration still occurs. This is because the map of FIG. 5 is simply the inverse of the map of FIG. 4 and does not take into account any delay in the intake airflow passing through the throttle valve.

Now, the following basic conditions are generally satisfied in the intake system.

[0071]

(Equation 5)

Gin: Mass of air passing through the throttle valve 7 per second (g / s) Go: Mass of air taken into the engine 1 per second (g / s) A (θ): Throttle opening Opening areas K1 to K5 corresponding to the degree .theta .: positive constants By solving the above, the following relationship is obtained between the intake pipe pressure Pm downstream of the throttle valve 7 and the throttle opening .theta. That is,

[0073]

(Equation 6)

There is generally a map characteristic between the torque T and the intake pipe pressure Pm shown in step 2000 in FIG.
Therefore, the intake pipe pressure Pm corresponding to the target torque TF is calculated from the map of step 2000, and after calculating Pm, the target throttle opening θ is calculated by the following equation. It should be noted that the Pm → θ conversion by the equation is complicated, so that the load on the CPU 50a is large because the calculation is complicated.
It can be said that the map search shown in the flowchart of FIG. 8 is more advantageous. That is, at step 2000, the target torque T
After F is converted to the intake pipe pressure Pm, AS is searched by the map shown in step 2001 instead of the equation. Then, the routine proceeds to step 2002, where the required throttle opening area Ad is calculated from the difference between AS (Ad) = AS + f (P
m). dAS / dt). At this time, f (Pm) is also calculated by a map search (not shown) instead of the equation. In addition,
AS is steady (when the throttle valve is stationary)
The opening area of the throttle valve is shown, and Ad is the finally required opening area of the throttle valve obtained by adding transient correction such as acceleration / deceleration to the steady opening area of the throttle valve. Next, the routine proceeds to step 2003, where the target throttle opening θ is determined from the opening area Ad using a map. In step 2003, a direct operation expression is used instead of a map.

[0075]

(Equation 7)

It is also possible to obtain θ using (K, K ′ are constants). By performing the calculation using the above method, the TF → θ conversion can be realized in consideration of the delay of the intake system. In the above embodiment, the accelerator operation amount sensor 41a is used as the accelerator operation amount detection means, and the throttle sensor 11, the intake air temperature sensor 13, the rotation sensor 19a, the water temperature sensor 23, and the intake pipe pressure sensor 14 are used as the engine operation state detection means. The gear position sensor 27a, the stroke sensor 64, and the tire pressure sensor 65 each correspond to a vehicle operation variable detection unit. In the processing of FIG. 3, step 1020 corresponds to torque estimation means, steps 1040 to 1060 correspond to estimated torque correction means, step 1070 corresponds to torque correction means, and step 1090 corresponds to prime mover control means.

In the above embodiment, the case of a manual transmission (MT) vehicle has been described. However, the present invention is also effective for an automatic transmission (AT) vehicle. However, a vehicle without a lock-up mechanism does not need the present invention because vehicle vibration does not occur due to internal slip of the torque converter.

In the above embodiment, step 4 in FIG.
At 004, the torque correction condition is not satisfied at the time of the auto cruise control, but steps 1040 and below can be executed during the cruise by the processing of the flowchart executed at the time of the auto cruise control in FIG. As a result, vehicle vibration at the time of starting the auto cruise control or changing the set vehicle can be prevented. That is, in step 5000, the cruise target opening θc is calculated as usual. In step 5001, θc
Drives the throttle valve 7. Step 5002
Then, it is determined whether or not the vehicle speed has actually become stable and steady. The method can be determined by checking the deviation from the auto cruise setting vehicle speed. Only when the vehicle is not traveling at a low speed, the torque correction condition is satisfied in step 5003, and θ obtained by TF → θ conversion may be used instead of θc.

Steps 1040 to 1080 in FIG.
When the rate of change of the estimated torque TT is large, that is, when the rate of change of the accelerator operation amount Ap is large, the filtering is automatically performed. At the time of acceleration, the characteristic of the target torque TF shown by the solid line in FIG. Become. Further, by controlling the throttle opening through step 1080, the throttle opening θ at the time of rapid acceleration decreases after the opening is once increased at the time of acceleration, in accordance with the characteristics of FIG.
The vehicle again increases and overshoots, and the longitudinal acceleration G of the vehicle follows the accelerator operation amount Ap almost without hunting, and overshoots only once and converges. With such acceleration characteristics, the driver can fully experience the feeling of acceleration, and the acceleration of the vehicle can be improved satisfactorily. In addition, since hunting is prevented at the same time by overshooting only once, extremely excellent ride comfort can be provided.

Next, another example of steps 1040 to 1060 in FIG. 3 for correcting the estimated torque TT so as to overshoot will be described. In the above example, step 104
0: Overshoot rate B / A based on engine operating condition
Is obtained, and the overshoot rate B is obtained in step 1050.
Although the filter is set based on / A, these processes may be executed by one process. For example, the map shown in FIG. 34 is set similarly to FIG.
(C) is associated with each of the filters shown in FIGS. Therefore, the filter can be set directly from the engine speed Ne and the accelerator operation amount Ap by using the map of FIG.

Further, the overshoot estimated torque T
p can be obtained. That is,

[0082]

(Equation 8)

Dt: Sampling time (calculation cycle) 1
/ TO: predetermined value (for example, 1 to 2 Hz) By repeating this calculation, the primary advance correction similar to that in FIG. 16 can be performed. Next, another example of step 1080 for realizing the TF → θ conversion in consideration of the delay of the intake system will be described. FIG. 9 shows a flowchart of the second alternative. This method
Although the above-described map of FIG. 5 is used, before the TF → θ conversion (step 3001) by the map search of FIG. 5, the value of TF is transiently corrected by a first-order advance system (step 30).
00). First-order advance correction is shown in FIG.
It has a characteristic like 0, that is, outputs a waveform converging to a steady value after overshoot in response to a stepwise increase in the target torque TF. This first-order advance correction characteristic can be calculated by the following equation.

T′i = L1 (Ti−Ti−1) −L2 (T′i−Ti) + T′i−1 T′i−1, T′i: Output previous value and current value L1, L2: Constant Ti-1, Ti: previous input value and current input value The first-order advance correction characteristic as shown in FIG. 10 can also be realized only by the filter as shown in FIG. This filter serves to amplify the target torque TF in a frequency region equal to or higher than a natural frequency f0, which is a hunting frequency specific to the vehicle, which will be described later. Can be.

The torque control may use not only the throttle but also fuel control, ignition control, EGR control, brake control, suppression control, boost pressure control, variable valve timing control (VVT), and the like. There is a limit to the responsiveness of the throttle, so there are times when the required torque cannot be achieved with the throttle alone. Therefore, better controllability is obtained by using a system that can control the torque other than by the throttle. The following are examples of the torque increase control and the torque decrease control that can be used together. Torque increase control a) Fuel control: Increase torque by increasing fuel.

A) Ignition control: The relationship between ignition timing and torque is generally as shown in FIG. The torque is increased by approaching the ignition timing at which the torque reaches a peak. C) EGR control: The relationship between the EGR rate and the torque is shown in FIG.
(B). EGR control valve 75
By fully closing, EGR is prohibited to increase the torque.

D) Supercharging pressure control: Supercharging pressure control valve 70
Is fully closed to increase the boost pressure and increase the torque. E) VVT: The relationship between the valve opening / closing timing and the torque is generally such that the opening timing is advanced and the closing timing is retarded, as shown in FIG. Control to the torque peak position. Torque suppression control a) Fuel control: Large torque suppression can be achieved by fuel cut. Further, the A / F may be controlled to the lean side.

A) Ignition timing: Torque is suppressed by retarding the ignition timing. C) EGR control: EGR rate is increased by valve 75 to suppress torque. D) Brake control: The torque transmitted to the wheels may be suppressed by increasing the brake oil pressure.

E) Exhaust pressure control: The exhaust pressure can be increased and the torque can be suppressed as the valve 73 is closed. F) VVT: The torque is suppressed by retarding the valve opening timing and advancing the closing timing of each of the intake and ventilation valves.

The present invention can also be applied to vehicles using various motors other than the internal combustion engine, such as electric vehicles.

[0091]

As described in detail above, in the torque control apparatus for a vehicle of the present invention, by correcting the estimated torque estimated by the torque estimating means with estimated torque correcting means,
The vehicle acceleration can be overshot only once so that a desired feeling of acceleration can be obtained . Further, the hunting of the vehicle acceleration can be performed by correcting the corrected estimated torque based on the value of the driving variable by the torque correcting means. Can be prevented.

As a result, the acceleration of the vehicle is reduced to a desired level.
After overshooting only once so as to be obtained, it is possible to converge to a predetermined value corresponding to the accelerator operation amount. In addition, according to the present invention, the estimated torque correcting means corrects the estimated torque based on the operating state detected by the engine operating state detecting means, so that the vehicle acceleration can be appropriately overshot according to the operating state. For this reason, the driver can fully feel the feeling of acceleration, and the acceleration of the vehicle can be improved satisfactorily. At the same time, hunting is prevented, so that an extremely excellent ride quality can be provided. Further, the estimated torque correcting means sets a target value of the overshoot rate based on the operating state detected by the engine operating state detecting means, and corrects the estimated torque based on the target value. In this case, the degree of the overshoot of the vehicle acceleration can be more appropriately controlled. Claim 3
As described, the estimated torque correction unit detects the accelerator operation amount detected by the accelerator operation amount detection unit, and
When the target value of the overshoot rate is set based on the operating state detected by the engine operating state detecting means and the estimated torque is corrected based on the target value, the following effects are further obtained. That is, in this case, since the accelerator operation amount detecting means is also referred to in addition to the engine operating state detecting means, the overshoot of the vehicle acceleration is more appropriately controlled according to the driver's request, and the driver is more appropriately controlled. You can experience a feeling of acceleration.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of the present invention.

FIG. 2 is a schematic configuration diagram illustrating an internal combustion engine of an embodiment.

FIG. 3 is a flowchart illustrating a main routine of vehicle torque control according to the embodiment.

FIG. 4 is a map showing a relationship between an accelerator operation amount and an estimated torque.

FIG. 5 is a map showing a relationship between a conventional estimated torque and a target throttle opening.

FIG. 6 is a map showing a relationship between an atmospheric pressure and a correction coefficient of an estimated torque.

FIG. 7 is a map showing a relationship between a water temperature and a correction coefficient of an estimated torque.

FIG. 8 is a flowchart showing conversion from a target torque to a throttle opening.

FIG. 9 is a flowchart illustrating another example of conversion from target torque to throttle opening.

FIG. 10 is a waveform chart showing characteristics of temporary advance correction of a throttle opening.

FIG. 11 is a Bode diagram illustrating a filter that temporarily advances the throttle opening.

FIG. 12 is a map showing a relationship between an engine operation state and an overshoot rate.

FIG. 13 is a graph showing a relationship between an engine output torque and an accelerator operation amount.

FIG. 14 is a map used to change an overshoot rate.

FIG. 15 is a Bode diagram showing a temporary advance filter of estimated torque.

FIG. 16 is a waveform chart showing characteristics of temporary advance correction of estimated torque.

FIG. 17 is a Bode diagram showing frequency characteristics of hunting.

FIG. 18 is a Bode diagram illustrating an inverse characteristic filter of a frequency characteristic.

FIG. 19 is a Bode diagram illustrating a vehicle stability compensation filter.

FIG. 20 is a Bode diagram showing a final filter for obtaining a target torque.

FIG. 21 is a flowchart illustrating a basic configuration of a process for calculating a target torque.

FIG. 22 is a flowchart illustrating a filter characteristic setting routine.

FIG. 23 is a flowchart illustrating a routine for calculating filtering.

FIG. 24 is a map showing a relationship between an operation variable and a natural frequency.

FIG. 25 is a map showing a relationship between an operation variable and a correction coefficient of an attenuation rate.

FIG. 26 is a map showing a relationship between a natural frequency, an attenuation rate, and a filter characteristic.

FIG. 27 is a map showing a relationship between a road surface condition and a setting of a high frequency region.

FIG. 28 is a flowchart illustrating a hunting cycle calculation routine.

FIG. 29 is a flowchart illustrating a routine for determining whether a torque correction condition is satisfied.

FIG. 30 is a flowchart showing a routine for determining a steady running.

FIG. 31 is a time chart showing a state of execution of a routine for determining a steady running.

FIG. 32 is a flowchart showing control during auto cruise.

FIG. 33 is a time chart showing changes in engine torque and vehicle G during acceleration.

FIG. 34 is a map showing a filter setting method according to another embodiment.

FIG. 35 is a Bode diagram showing a filter in the embodiment.

FIG. 36 is a graph showing the relationship between various torque controls and engine torque.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine 7 ... Throttle valve 9 ... Step motor 14 ... Intake pipe pressure sensor 23 ... Water temperature sensor 27a
... Gear position sensors 31a, 33a, 35a, 37a ... Wheel speed sensors 41a ... Accelerator operation amount sensors 41b
... accelerator full-close sensor 50 ... ECU 60a-60d ... suspension
62 air-fuel ratio sensor 63 G sensor 64 suspension deflection sensor 65 tire pressure sensor 77 variable valve timing device

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-78542 (JP, A) JP-A-4-41948 (JP, A) JP-A-1-125567 (JP, A) (58) Field (Int. Cl. ⁷ , DB name) F02D 41/00-45/00 395

Claims (3)

(57) [Claims] 1. An engine that drives a vehicle, an accelerator operation amount detector that detects an accelerator operation amount, an engine operation state detector that detects an operation state of the engine, and an operation variable related to a vibration system of the vehicle Vehicle operating variable detecting means for detecting the value of the following; torque estimating means for estimating the torque required of the prime mover based on the detection results of the accelerator operation amount detecting means and the engine operating state detecting means; A torque correcting means for correcting the estimated torque estimated in the above in a direction for preventing hunting of the vehicle acceleration based on the value of the driving variable; and a target torque obtained by correcting the estimated torque by the torque correcting means. And a motor control means for controlling the motor based on the torque of the engine. Based on the operating conditions, the estimated torque as the desired acceleration feeling is obtained, provided the estimated torque correction means for correcting to converge overshot once, corrected by the estimated torque compensator A torque control device for a vehicle, wherein the later estimated torque is corrected by the torque correction means. 2. The method according to claim 1, wherein the estimated torque correcting means sets a target value of an overshoot rate based on the operating state detected by the engine operating state detecting means, and corrects the estimated torque based on the target value. The torque control device for a vehicle according to claim 1, wherein: 3. The accelerator operation amount detected by the accelerator operation amount detection means,
3. The vehicle according to claim 2, wherein a target value of the overshoot rate is set based on the operating state detected by the engine operating state detecting means, and the estimated torque is corrected based on the target value. Torque control device.