JPH0733778B2 - Vehicle drive force control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vehicle driving force control in which a throttle valve mechanically uncoupled from an accelerator operator is controlled to open and close according to an operation of the accelerator operator. Regarding the device.

(Prior Art) A conventional vehicle driving force control device is disclosed in
The device described in JP-A-60-431332 is known.

This conventional device is a vehicle engine output control device that controls the engine output by changing the fuel supply amount to the engine according to the accelerator pedal position, in a drive wheel rotation speed detection means, a non-drive wheel rotation speed detection means, Calculating means for calculating the slip ratio between the tire and the road surface from the outputs of both detecting means, comparing means for comparing the calculated slip ratio and the set slip ratio, and control based on the accelerator pedal position when the calculated slip ratio is large. It was characterized in that it was provided with a slip ratio control means for outputting a signal for forcibly reducing the fuel supply to the engine in preference to the output.

(Problems to be Solved by the Invention) However, in such a conventional vehicle driving force control device, when the set slip ratio is exceeded, the fuel supply to the engine is reduced to avoid slip and to avoid slip. After that, since the control for returning to the state before the slip avoidance is performed as it is, there is a problem that the similar slip occurs again after the slip is avoided.

Further, when the vehicle travels on a road having a low friction coefficient in which drive wheel slip is likely to occur, a hunting state in which a decrease in fuel supply and an increase in fuel supply to the engine are repeated irrespective of the accelerator operation is generated, causing jerky vibration.

Also, when the slip ratio is large, the engine drive force is forcibly controlled prior to the throttle opening control based on the accelerator pedal position. Therefore, during slip prevention control, the correspondence relationship between the accelerator pedal operation and the engine drive force is controlled. Is lost, and a feeling of strangeness in accelerator operation occurs.

Therefore, in order to solve these problems, the present applicant previously filed an application for Japanese Patent Application No. 61-157389.

However, in this prior application, when the slip ratio exceeds the set slip ratio, based on the control characteristic map at that time,
Since it was configured to select a map lower than that map, when the slip ratio is small, the map moves to the upper map,
As a result, when the slip ratio becomes large, it is unreasonable to select the lower map based on the map at that time without considering the response delay of the engine.

In other words, selecting a new map based on the current map, although it has no meaning, causes acceleration failure or slip reoccurrence depending on the setting.

Also, when the slip ratio is large, the driving force is uniquely reduced, so when the A / T vehicle is upshifted,
The change in the drive shaft speed due to the change in the gear ratio is transmitted to the tire side due to the small road surface load (low μ road), and the slip ratio increases. Will be able to control the decrease of.

For this reason, the slip due to the excessive engine output originally can be prevented, but even when the above-mentioned slip peculiar to the A / T vehicle is reduced, the driving force is reduced to cause poor acceleration. That is, the slip peculiar to the A / T vehicle is not the slip due to the excessive engine output, but is simply the apparent slip due to the change in the gear ratio, so that the driving force need not be reduced. Further, in the configuration in which the map is shifted to the lower position when slipping, a feeling of poor acceleration is caused due to insufficient driving force after upshifting.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above-mentioned problems, and in order to achieve this object, the present invention uses the following solving means.

The solution means of the invention according to claim 1 will be described with reference to the claim correspondence diagram shown in FIG. 1. The road surface of the tire is determined by the wheel speed obtained from the driving wheel speed detection means a and the vehicle body speed obtained from the vehicle body speed detection means b. Slip ratio calculating means c for calculating a slip ratio between the two, accelerator operation amount detecting means d for detecting an accelerator operation amount with respect to an accelerator operator, shift up detecting means e for detecting a shift up state, and an actual throttle of a throttle valve. An actual throttle opening value detecting means f for detecting an opening value, a map setting means g for setting a plurality of relations of the throttle opening with respect to the accelerator operation amount as a control characteristic map, and basically the slip ratio. Whenever exceeds the set slip ratio, the increase ratio of the throttle opening to the accelerator operation amount is decreased from the selected control characteristic map. Select the lower control characteristic map, but if a shift-up state is detected, even if the slip ratio exceeds the set slip ratio within a predetermined time from the shift-up detection, the shift to the lower control characteristic map described above is performed. The target throttle opening value is obtained by the map selecting means h for prohibiting the control, the control characteristic map selected by the map selecting means h, and the accelerator operation amount, and at the time of shift-up, the target is set for a predetermined time from the shift-up detection. Target throttle opening value setting means i for fully closing the throttle opening value, and slot valve opening / closing control for outputting a control signal for matching the actual throttle opening value with the target throttle opening value to the throttle actuator j. Means k
And are provided.

(Operation) When a drive wheel slip occurs during traveling on a low friction coefficient road or during acceleration traveling on a high friction coefficient road, each time the slip ratio exceeds the set slip ratio in the map selecting means h. The lower control characteristic map in which the increase rate of the throttle opening with respect to the accelerator operation amount is reduced from the selected control characteristic map is selected.

Therefore, every time the slip ratio exceeds the set slip ratio, the throttle valve operates in the closing direction, so that the driving force is reduced according to the occurrence of the drive wheel slip, and the drive wheel slip is prevented.

If the slip ratio does not exceed the set slip ratio with the lower control characteristic map selected, the selected lower control characteristic map is not immediately returned to the driving force level before the map fell. Therefore, re-slip immediately after slip prevention is prevented, and hunting due to increase / decrease in driving force, such as fuel cut control, does not occur during driving force control.

On the other hand, when the shift-up state is detected, the map selecting means h prohibits the shift to the lower control characteristic map even if the slip ratio exceeds the set slip ratio within a predetermined time from the shift-up detection. .

That is, even if a drive wheel slip occurs within a predetermined time after the shift-up is detected, this slip is regarded as an apparent slip due to a change in the gear ratio, and in this case, the map drop is prohibited. After shifting up, it is possible to prevent the feeling of acceleration from being deteriorated due to insufficient driving force.

When shifting up, the target throttle opening value setting means i fully closes the target throttle opening value for a predetermined time from the shift-up detection, and the throttle valve is fully closed.

That is, in order to achieve a feeling of acceleration after a shift-up, it is sufficient to execute the map drop prohibition as described above, but a slip caused by a change in the gear ratio is allowed during the shift-up. . Therefore, by fully closing the throttle valve for a predetermined time after the shift-up detection, the occurrence of slip due to a change in gear ratio can be suppressed.

As a result of performing the map drop prohibition and the throttle fully closed control at the time of upshifting, both slip suppression at the time of upshifting and ensuring acceleration feeling after upshifting can be achieved.

(Examples) Examples of the present invention will be described in detail below with reference to the drawings.

In describing this embodiment, a drive force control device applied to a rear-wheel drive vehicle will be taken as an example.

First, the configuration of the embodiment will be described.

As shown in FIG. 2, the power train P of the rear-wheel drive vehicle to which the driving force control apparatus A according to the embodiment is applied includes an engine 10,
It has an automatic transmission 11, a propeller shaft 12, a rear differential 13, rear drive shafts 14 and 15, and rear wheels 16 and 17.

The driving force control apparatus A of the embodiment mechanically disconnects an accelerator pedal 20 which is an accelerator operator and a throttle valve 22 which is provided in a throttle chamber 21 which is an intake system of the engine 10 from an accelerator control wire or the like. Accelerator pedal 20 and throttle valve instead of the mechanical connection of
22 is a control device provided between the input device and
A rear wheel rotation speed sensor 30, a right front wheel rotation speed sensor 31, a left front wheel rotation speed sensor 32, and an accelerator potentiometer 33 are provided, a throttle valve control circuit 34 is provided as an arithmetic processing means, and a step motor 35 is provided as a throttle actuator. The throttle valve control circuit 34 receives a gear position command signal from the A / T control circuit 36 that controls the shift of the automatic transmission 11, and detects the gear position by this signal.

The rear wheel rotation speed sensor 30 is a drive wheel speed detecting means, is provided on the input shaft portion of the rear differential 13, and outputs a rear wheel rotation signal (vr) corresponding to the rear wheel rotation speed V _R.

An optical sensor, a magnetic sensor, or the like is used as the rear wheel rotation speed sensor 30, and when a pulse signal is output as the rear wheel rotation signal (vr), the throttle valve control circuit 34
In the input interface circuit 341 inside, the F / V converter converts to a voltage according to the frequency of the pulse signal, and the A / D converter converts the voltage value to a digital value.
342 and memory 343.

The right front wheel rotation speed sensor 31 and the left front wheel rotation speed sensor 32
Is a vehicle body speed detecting means, which is provided at each accelerator portion of the front wheels 18 and 19, and outputs a right front wheel rotation signal (vfr) and a left front wheel rotation signal according to the right front wheel rotation speed V _FR and the left front wheel rotation speed V _FL. Output signal (vfl).

The signal conversion for the CPU 342 of the throttle valve control circuit 34 to read the output signals from both the front wheel rotation speed sensors 31 and 32 is performed in the same manner as the rear wheel rotation speed sensor 30.

The accelerator potentiometer 33 is a means for detecting the absolute accelerator operation amount 1, is provided at the position of the accelerator pedal 20, and outputs an absolute accelerator operation amount signal (l) corresponding to the absolute accelerator operation amount 1.

Since the output signal from the accelerator potentiometer 33 is an analog signal based on a voltage value, it is converted into a digital value by the A / D converter of the input interface circuit 341 and read into the CPU 342 or the memory 343.

The throttle valve control circuit 34 processes the input information from the input sensor and the information temporarily or preliminarily stored in the memory 343 in accordance with a predetermined arithmetic processing procedure and outputs a pulse to the step motor 35 which is a throttle actuator. An electronic circuit centered on a microcomputer that outputs a control signal (c). As internal circuits, an input interface circuit 341, a CPU (central processing unit) 342, a memory (RAM, ROM) 343, and an output interface circuit 344 are provided. I have it.

As shown in FIG. 3, the memory 343 having a function as map setting means of the throttle valve control circuit 34 has eight types of upper and lower limits as a control characteristic map of the throttle opening θ with respect to the absolute accelerator operation amount 1. The area control characteristic maps # 0 to # 7 are set, and each of the maps # 0 to # 7 is set.
# 7 corresponds to the throttle opening θ that produces the maximum driving force when the road surface friction coefficient μ is set to Table 1 below.

The upper limit of each map # 0 to # 7 is the absolute accelerator operation amount.
It is formed by the line connecting the throttle opening maximum value at 3/4 and the zero reference point, and the line of the throttle opening maximum value at the absolute accelerator operation amount 3/4 to 4/4, and the lower limit is the absolute accelerator operation amount. It is formed by the line connecting the throttle opening maximum value at the amount of 4/4 and the Zel reference point.

The memory 343 of the throttle valve control circuit 34 stores the fourth
As shown in the figure, the relationship characteristic between the relative accelerator operation amount Δl and the throttle opening change amount Δθ is set as a cubic curve characteristic.

The throttle valve control circuit 34 includes a slip ratio calculating means, an actual throttle opening detecting means, and a slip ratio calculating means described in the claims.
A map selecting means, a target throttle opening value setting means, and a slot valve opening / closing control means are included.

It should be noted that the actual throttle opening detection means is the S from the CPU 342 of the throttle valve control circuit 34 to the output interface circuit 344.
The memory 343 receives the TEP command signal at the same time, and this memory 343 receives it.
Is a means of an internal circuit configuration for writing and counting the number of STEPs, and the actual throttle opening value θ ₀ is read to the CPU 34 at any time according to a read command from the CPU 342.

Further, the map selecting means includes a map ascending selecting means and a map dropping selecting means.

The step motor 35 is an actuator that opens and closes the throttle valve 22 and includes a rotor and a plurality of stators having an excitation winding, and a forward rotation direction and a reverse rotation direction depend on how a pulse is applied to the excitation winding. Rotate one step at a time.

Next, the operation of the first embodiment will be described.

First, the flow of the throttle valve opening / closing control operation in the CPU 342 will be described with reference to the flowchart of the main routine shown in FIG. 5 and the flowchart of the subroutine shown in FIG.

Note that the processing in the main routine of FIG. 5 is performed in a predetermined cycle (for example, 20
msec) is a constant time interrupt process, and the process in the subroutine of FIG. 6 is appropriately started in the main routine according to the signal output cycle to the step motor 35 determined by this constant time interrupt. oci (output compare interrupt) interrupt processing.

(A) Initial setting In the main routine shown in Fig. 5, insert the engine key into the key cylinder and turn the ignition switch from OFF to O.
Starting is started from the time of switching to N, and at the time of the first processing operation, it is judged whether it is the first time (step
100), and proceed to the next initializing step 101.

In this initialization step 101, MAPFLG
= 0, and clears all other information such as FLG and reference values l ₀₀ and θ ₀₀ .

(B) Slip ratio calculation process The calculation process of the slip ratio S between the tire and the road surface is performed in steps.
Steps 102 to 107 are performed.

First, based on the input signals from the respective rotation speed sensors 30, 31, 32, the rear wheel rotation speed V _R , the right front wheel rotation speed V _FR , the left front wheel rotation speed V
_FL is read (step 102), then front wheel rotation speed V _F
Is calculated (step 103).

The formula is And is calculated by the average value.

Next, it is determined whether or not the rear wheel rotation speed V _R, which is the driving wheel, is 40 km / h or more (step 104). If V _R ≧ 40 (km / h), the process proceeds to step 105, and in this step 105 The slip ratio S is calculated.

The calculation formula of the slip ratio S is Is.

When it is determined in step 104 that V _R <40 (km / h), the front-rear wheel rotation speed difference ΔV (= V _R −V _F ) is calculated (step 106) and calculated. The slip ratio S is set according to the front-rear wheel rotation speed difference ΔV (step 107).

Accordingly, the slip ratio S obtained in step 105 or step 107, when expressed in the graph becomes as shown in FIG. 7, the set slip ratio S ₀ in the control operation of the slip ratio S is less, S ₁ , the threshold when compared to S _2.

(C) Control Information Setting Process The control information setting process used in the map selecting process and the accelerator work determining process, which will be described later, is performed in steps 150 to 154 and steps 251 to 255.

First, sampled at two periods before treatment, the accelerator pedal depression amount that is treated as the last absolute accelerator operation amount l ₁ in the process of one cycle before is set as a second preceding absolute accelerator operation amount l ₂ (step 150).
Further, the accelerator pedal swing amount sampled in the process one cycle before and treated as the absolute accelerator operation amount l ₀ this time is set as the previous absolute accelerator operation amount l ₁ (step 151). Next, the current accelerator pedal depression amount is used as the absolute accelerator operation amount l ₀ this time, and the current throttle valve opening is the actual throttle opening value θ _0.
Is sampled and loaded as (step 15
2). Next, the set absolute absolute accelerator operation amount l ₀
By subtracting the absolute accelerator operation amount l ₁ from the previous time from, the current relative accelerator operation amount ΔL _0, which is the amount of change in the accelerator pedal depression amount from the processing one cycle before, is calculated (step 153). The previous relative accelerator operation amount ΔL, which is the amount of change in the accelerator pedal depression amount that changed from the processing two cycles ago to the processing one cycle ago by subtracting the absolute accelerator operation amount l _{2 two} times before from the accelerator operation amount l _{1. 1} is calculated (step 154).

In steps 251-255, the control characteristic map MAPFLG is used.
The data is stored up to a predetermined time before (here, 600 msec before).

The counter CTR is a predetermined number of MAPFLG (in the embodiment, 600 msec / 2
It is a counter that determines the number of loops to be stored in the address of 0 mse = 30), and loops 29 times between step 251 and step 253 and then proceeds to step 254 and thereafter. In step 252, an address obtained by adding the value of CTR to the memory address in which the value of MAPFLG is stored (“(MAPFLG)
The value of “+ CTR”) is stored in the memory address of +1. MPAF of the past in memory of +1 address sequentially according to the loop
Since the value of LG is stored, steps 123 and 124 to be described later
And the value of MFPFLG before 600 msec used in steps 129 and 130 MA
POLD is remembered at address MAPFLG + 30. Suntep 25
In step 4, `` MAPF obtained in the 29th loop of step 252
"LG + 30" contents, that is, the value 600msec before MAPFLG is M
Remember in APFLG.

By the clearing process of the counter CTR shown in step 253, MAPOLD is set to "MAPFLG before 600 msec" once in one control cycle.
Is rewritten as "value of".

(D) Map upstream selection processing This processing is performed when the area control characteristic is in the area control characteristic map lower than the uppermost area control characteristic map by the yap drop selection means described later.

The map ascending selection process for selecting a higher region control characteristic map in which the increase rate of the throttle opening θ with respect to the absolute accelerator operation amount 1 is selected from the currently selected region control characteristic map is step 110 to step 119 and step 161 to
This is done in step 163.

First, it is determined whether the absolute accelerator operation amount l ₀ this time is greater than or equal to the high set accelerator operation amount L _H (step 11
Five). The high set accelerator operation amount l _H in the first embodiment is
When the maximum accelerator operation amount is set to 1, the kickdown-like region boundary is set to l _H = 3/4.

Further, it is determined whether or not the absolute accelerator operation amount l ₀ this time is equal to or higher than the low set accelerator operation amount l _H (step 25
0). The low set accelerator operation amount l _L in the first embodiment is
I _L = 1/4 is set as the low accelerator operation area boundary.

Then, in step 115, l ₀ <l _H and in step 250, l ₀ > l _L
If it is determined that (ie, if l _L ≤ l ₀ <l _H ), whether the current relative accelerator operation amount ΔL ₀ is ΔL ₀ > 0, that is, whether or not the accelerator pedal 20 is being depressed. It is determined (step 110), and then the step rate S is S
It is determined whether or not ≦ S ₀ (for example, S ₀ = 0.1), that is, whether or not drive wheel slip has occurred at the set slip ratio S ₀ or less (step 111), and then the actual throttle opening value It is determined whether or not θ ₀ is θ ₀ ≧ θ _MAX , that is, whether the actual throttle opening value θ ₀ is the throttle opening upper limit value θ _MAX according to the previously selected region control characteristic map (step 112), and the next MAPFLG Is MAPFLG ＝
Map # 1 that is 0 or not, that is, map up
It is determined whether or not it is # 7 to # 7 (step 113), the process proceeds to step 114 only when all of these map ascending conditions are satisfied, and the MAPFLG number (# 1 to # 7) is lowered by 1 (step 1). 114) 1 for the area control characteristic map
Move to a higher level map. Incidentally, the steps 110-
When any one of the map ascending conditions described in step 113 is not satisfied, the area control characteristic map selected at that time is held until all of the map ascending conditions are newly satisfied.

If l ₀ ≧ l _H is determined in step 115, it is determined whether the slip ratio S is S ≦ S ₀ (for example, S ₀ = 0.1) (step 116), and S ≦ S ₀ Step 117
Then, it is judged whether or not the timer is up. If the timer is not up, the flow advances to step 118 to increase the timer value. In this way, step 115 → step 1
The sequence of 16 → step 117 → step 118 is continuously repeated, and when it is determined that the timer is up in step 117, it is determined in step 161 whether MAPFLG is MAPFLG = 0, that is, map # 1 capable of ascending the map. It is determined whether or not # 1 to # 7, and if l ₀ ≧ l _H , S ≦ S ₀ continues for a predetermined time, and if all the map ascent conditions of MAPFLG ≠ 0 are satisfied, the process proceeds to step 162, and the MAPFLG number ( # 1 to #
7) is lowered to the first position, and the area control characteristic map moves to a map one step higher. Note that steps 119 and 163 are tie clear steps, and the slip ratio S
Is> S ₀ and when the map up control is completed, the timer is cleared for the next timer value count. In addition, the set time T _{0 for} which the timer is up in the first embodiment
Is set to 0.8 sec.

(E) Map drop selection process The map drop prohibition process at upshift is a step
In step 260 to step 269, the map drop selection processing for selecting a lower region control characteristic map in which the increase rate of the throttle opening θ with respect to the absolute accelerator operation amount 1 is lower than the currently selected region control characteristic map is executed. , Step
It is performed from 120 to step 131.

First, the map drop prohibition processing during upshift will be described. In step 260, the current gear position ATPOS
Is read, and in step 261, the current gear position ATPOS is
And the gear position ATPOSO one control cycle before are compared and AT
When POS> ATPOSO, that is, during upshifting, the routine proceeds to step 262, where the map drop prohibition flag ATFLAG is set to "1", and at step 263 the map drop prohibit time timer ATTMR is cleared. Rewrite ATPOS to ATPOSO in 264 and store.

When the predetermined time K has not elapsed from the upshift and the map drop prohibition flag ATFLAG = 1, the process proceeds from step 265 to step 266, and it is determined whether the predetermined time K (eg, K = 1 sec) has elapsed in ATTMR. If it has not elapsed (ATTMR <K), ATTMR is incremented (step 267) and the process proceeds to step 264.

The flow from step 265 to step 267 is repeated, and when ATTMR = K is reached in step 266, the process proceeds to step 268, in which the muff drop prohibition is released and ATTMR and
ATFLAG is cleared, ATPOS is rewritten and stored in ATPOSO in step 269, and the process proceeds to step 120 and subsequent map dropping processing.

If it is not upshift, step 260 →
Step 261-> step 265-> step 269, without any prohibition of map drop, step 12
Proceed to the map drop processing after 0.

Next, the map drop processing will be described. The slip ratio S
And the first set value S ₁ (for example, S ₁ = 0.1) are compared, and it is determined whether S> S _1, which is the upper limit of dropping one map, that is, whether drive wheel slip has occurred (step 120), if S> S ₁ , go to the next step 120 FL
Whether or not AG · A = 0 is determined, and if FLG · A = 0, FLAG · A = 1 is set (step 122), and in the next step 123, the value MAPOLD 600 msec before MAPFLG (step 254). Is determined to be 7, and when MAPOLD ≠ 7, the condition of dropping one map is satisfied, so the MAPFLG number (# 0 to # 6) is increased by 1, and that value is the MPFLG address. (Step 124).

After dropping one map in step 124,
In step 120, it is determined that S ≦ S ₁ , FLAG · A = 0 is set after step 125, and unless S> S ₁ is newly established, the selection process of dropping one map is not performed,
The area control characteristic map selected by dropping one map in step 124 is held as it is. However, FLAG
If A = 1, the process proceeds from step 121 to step 126, and the case is satisfied when the condition of S> S _{2 to} be dropped, which will be described later, is satisfied.

In addition, when proceeding from the step 124 to the next step 126,
The slip ratio S and the second set value S ₂ (for example, S ₂ = 0.3) are compared, and whether S> S ₂ which is the condition for dropping one map, that is, whether excessive drive wheel slip has occurred If S> S ₂ , the process proceeds to the next step 127, and it is determined whether FLAG · B = 0. If FLAG · B = 0, FLAG · B = 1 is set (step 12
8) In the next step 129, the value MAPOL 600msec before MAPFLG
It is determined whether D (step 254) is 7, and MAPOLD ≠ 7.
When, the condition for dropping one map (S> S ₂ and MAPOLD ≠ 7)
MAPOLD number (# 0 to # 6) is 1 for children who are satisfied with
As the region control characteristic map that has been raised, the map moves to the map one step lower and the value of MAPOLD is stored in MAPFLG (step
130).

After dropping one map in step 130,
In step 126, it is determined that S ≦ S _2, and after step 131, FLAG · B = 0 is set, and unless S> S ₂ is newly established, the selection process of dropping one map is not performed.
The area control characteristic map selected by dropping one map in step 130 is retained as it is.

(F) Setting of area control characteristic map In step 140, an area control characteristic map having the same number as the MAPFLG number selected by the progress of the map ascending selection processing and the map omission selection processing described above is set.

(G) When the map holding process l ₀ ≦ l _L , the steps 110 to 114 of the map ascending selection process are bypassed at the above-mentioned step 250, so that the currently selected area control characteristic map is held as it is. It will be.

When l ₀ ≤l _L , naturally l ₀ ≤l _H , so step 11
No signal is input to the other map up-link selection processing of 6 to step 119 and step 161 to step 163.

Further, in step 164, it is judged whether or not the absolute accelerator operation amount l ₀ this time exceeds the low set accelerator operation amount l _L , and when l ₀ > l _L , the accelerator lock determination process described later in steps 155 to 157 is executed. If l ₀ ≦ l _L, no matter what accelerator operation is performed, steps 158 and 159
To update the reference values l ₀₀ and θ ₀₀ , the throttle opening θ along the lower limit of the selected region control characteristic map
Becomes

The low set accelerator operation amount l _L in the first embodiment is set to 1 _L = 1/4 as a small accelerator operation area boundary.

Further, when l ₀ ≦ l _L , in step 250 described above, steps 110 to 114 of the map ascending selection processing are bypassed, so that the selected area control characteristic map is retained as it is.

(H) Accelerator Work Discrimination Processing In the accelerator work discrimination processing, since the reference for obtaining the relative accelerator operation amount ΔL is the constant speed traveling accelerator operation, in order to determine whether or not the constant speed traveling accelerator operation is performed, This is the process performed in steps 155 to 159 based on the information obtained in steps 150 to 154.

First, the determination logic of the accelerator work is that the accelerator pedal 20 is being continuously operated in the stepping direction from the time of processing two cycles before using the previous relative accelerator operation amount ΔL ₁ and the current relative accelerator operation amount ΔL _0. When the acceleration accelerator operation determination is made (affirmative in step 155, affirmative to step 156), or when the deceleration accelerator operation determination is made during the subsequent returning operation (negative in step 155, (Negative in step 157), the process proceeds to the next step 160.

If the accelerator pedal 20 is stopped and held at that position (negative in step 155, affirmative in step 157), the operating direction of the accelerator pedal 20 is switched from the stepping direction to the returning direction (step 155). Is positive, negative in step 156) or vice versa (negative in step 155, positive in step 157), the change amount of the accelerator pedal depression amount includes 0 from an increase including 0. It is determined that the accelerator is operating at a constant speed that decreases or increases, and the routine proceeds to step 158, where the absolute accelerator operation amount l ₀ is set as the access operation amount reference value l _{00, and the} operation proceeds to step 159. The throttle opening value θ ₀ is set as the throttle opening reference value θ ₀₀ .

(I) Relative accelerator stroke calculation processing After the above-described accelerator work determination processing is performed, the routine proceeds to step 160, where the relative accelerator operation amount ΔL is calculated.

The calculation formula for this relative accrel manipulated variable ΔL is ΔL = l ₀ −l
_Since it is ₀₀ , at the time of acceleration accelerator operation or deceleration accelerator operation, it is calculated as the accelerator operation change amount from the time when the constant speed traveling accelerator operation is first performed to the absolute accelerator operation amount l ₀ this time. At the time of the first constant speed traveling accelerator operation, ΔL = l ₀₀ −l _{00 and the} relative accelerator operation amount ΔL
Is zero.

(E) Throttle opening change amount calculation In step 170, the throttle opening change amount Δθ is calculated based on the relative accelerator operation amount ΔL obtained in step 160 and the ΔL-Δθ characteristic diagram shown in FIG.

(L) Target throttle opening value setting process Temporary target throttle opening value θθ obtained by the throttle opening reference value θ ₀₀ and the throttle opening change amount Δθ calculated in step 170, and set in step 140 Region control characteristic map and absolute accelerator operation amount this time
l ₀ (or the accelerator operation amount reference value l ₀₀ ) is compared with the throttle opening upper limit value θ _MAX and the throttle opening lower limit value θ _MIN to set the target throttle opening value θ ^*. It is performed from 180 to step 185.

First, in step 180, the temporary target throttle opening degree value θθ is set to the throttle opening reference value θ ₀₀ and the throttle opening change amount Δθ.
Arithmetic expression for adding the door, is obtained by θθ = θ ₀₀ + Δθ.

The process of comparing the provisional target throttle opening value θθ with the throttle opening upper limit value θ _MAX and the throttle opening lower limit value θ _MIN first determines whether the provisional target throttle opening value θθ is greater than or equal to the throttle opening upper limit value θ _MAX. Judged (step 181),
throttle opening upper limit theta _MAX is set as the target throttle opening value theta ^* in the case of θθ> θ _MAX (Step 18
2). If θθ ≤ θ _MAX , it is determined whether the provisional target throttle opening value θθ is less than or equal to the throttle opening lower limit value θ _MIN (step 183). If θθ <θ _MIN , the throttle opening lower limit value θ _MIN is set as the target throttle opening value θ ^* (step 184). Also, θ _MIN ≤ θ θ ≤
In the case of θ _MAX , the provisional target throttle opening θθ is set as it is as the target throttle opening value θ ^* (step 185).

That is, the target throttle opening degree value θ ^* is set as a value existing in the area of the selected area control characteristic map.

(2) Throttle valve opening / closing control process When the target throttle opening value θ ^* is determined by the above-mentioned target throttle opening value setting process, the actual throttle opening value θ
_The processing for operating the throttle valve 22 in the direction in which ₀ matches the target throttle opening value θ ^* is performed in steps 200 to 202 in the main routine of FIG. 5 and steps 300 to 304 in the subroutine of FIG. .

First, the deviation ε is calculated by subtracting the actual throttle opening value θ ₀ from the target throttle opening value θ ^* (step 20
0), based on the deviation ε obtained by this calculation, calculation of the motor speed of the step mode 35, determination of forward rotation, reverse rotation, and holding, and the activation cycle of the oci interrupt routine are obtained (step 201). The oci interrupt routine (FIG. 6) is started according to the operation control content of the step motor 35 set in 201 (step 202).

Next, a flowchart of the oci interrupt routine will be described with reference to FIG.

First, a determination is made as to whether or not a hold command output for holding the state of the step motor 35 as it is is being output (step 300),
When the holding command is output, the fixed-side excitation state of the step motor 35 is held (step 301).

When the hold command is not output, the step motor 35
It is determined whether or not the reverse rotation command for reversing is output (step 302). When the reverse rotation command is output, S
TEP is set to STEP-1 (step 303), and the pulse signal for obtaining STEP-1 is output to the step motor 35 (step 301). Further, at the time of outputting a normal rotation command for rotating the step motor 35 in the normal direction, STEP is set to STEP + 1 (step 304) and a pulse signal for obtaining STEP + 1 is output to the step motor 35 (step 301).

The oci interrupt routine is repeated within the start cycle of the main routine according to the start cycle set in step 201.

With the control flow described above, the map up and map down control operations are as follows.

Map up control, if the following conditions are satisfied,
This is performed by raising the control characteristic map by one.

When the accelerator operation amount l ₀ is l _L ≦ l ₀ <l _H , the slip ratio S does not exceed the set slip ratio S ₀ during the depression operation,
When the actual throttle opening value θ ₀ is the throttle opening upper limit value θ _MAX according to the selected region control characteristic map (step 110 to step 114).

When the accelerator operation amount l ₀ is l ₀ > l _H , the slip ratio S
When the value does not exceed the set slip ratio S ₀ for a predetermined time (step 116 to step 163).

The map drop control is performed when the slip ratio S exceeds the set slip ratio S _1, and when the slip ratio S exceeds the set slip ratio S ₂ , one or two control characteristic maps selected 600 msec before. This is performed by dropping the one-sheet map (step 120 to step 130).

However, during the predetermined time K from the upshift, even if the step ratio S exceeds the set slip ratios S ₁ and S ₂ , the map drop processing is prohibited regardless of the slip ratio S (step 260 to step 260). 269).

Therefore, the shift position, the engine speed, the wheel speed, and the time chart of the map at the time of starting when an upshift occurs from the D1 speed to the D2 speed are as shown in FIG. 8, and slip occurs due to excessive driving force. In this case, map drop control is performed (# 6 → # 7), but if slip occurs due to a change in gear ratio, even if the map drop condition is satisfied as the slip ratio condition, It is held at 3.

Then, during the 1 → 2 shift in which the engine speed rapidly decreases, as shown by the dotted line in FIG. 8, the throttle valve 22 is temporarily fully closed for a predetermined time in order to suppress the slip due to the gear ratio change. The control is used in combination with the map drop prohibition control.

As described above, in the driving force control device of the first embodiment, the effects listed below can be obtained.

The set l-θ control characteristic map is the area control characteristic map, and the opening / closing control of the throttle opening θ is performed based on the relative accelerator operation amount ΔL based on the absolute accelerator operation amount 1 during the constant speed traveling operation. Because it is
Since the opening / closing control gay of the throttle valve 22 is obtained in accordance with the accelerator work in the map area, it is possible to ensure both good acceleration of the vehicle and prevention of large vehicle speed changes during constant-speed running operation.

As shown in FIG. 4, the ΔL-Δθ characteristic is a cubic curve-like characteristic, so that the junk shank feeling when the accelerator is slightly depressed is prevented, and the high acceleration performance is achieved when the accelerator is slightly depressed. To be done.

As shown in FIG. 7, the slip ratio S is determined by the front-rear wheel rotation speed difference ΔV when the vehicle body speed is low.
High detection accuracy and high calculation accuracy are not required at low vehicle speeds where the slip ratio S changes due to, and map up control, map drop control, and throttle front close control are performed by the calculated value of the slip ratio S due to calculation error. Nor.

In the small accelerator operation amount region where the absolute accelerator operation amount l ₀ is l ₀ ≤l _L this time, the region control characteristic map selected at that time is held without going up the map. Correspondence with degree θ is stable,
The throttle valve 20 does not open wide even if the accelerator pedal 20 is slightly depressed to move up the map, and it is possible to prevent large torque fluctuations in the low accelerator operation amount region and to perform delicate accelerator operation. Is.

When l ₀ ≤l _L when starting when the vehicle is stopped, if the lower limit of the region control characteristic map is followed, the control gain of the throttle opening θ with respect to the absolute accelerator operation amount l should be minimized. It becomes possible to perform a more delicate accelerator operation.

This time, when the absolute accelerator operation amount l ₀ is l _L <l ₀ <l _H , the map ascending control of the region control characteristic map in the intermediate accelerator operation amount region is such that the slip ratio S is S when the accelerator pedal 20 is depressed. Since it is performed on condition that ≦ S ₀ , how to open the throttle valve 22 corresponds to the accelerator operation, the driver does not feel uncomfortable, and a natural acceleration feeling can be obtained.

Further, since the condition is that the actual throttle opening value θ ₀ is the throttle opening upper limit value θ _MAX , there is no sudden increase in engine driving force.

This absolute map the uplink control region control characteristic map of the accelerator operation amount l ₀ is a high accelerator operation amount region in l ₀ ≧ l _H is the slip ratio S is continuously state set time T ₀ of the S ≦ S ₀ Since it is performed under the condition that the driver is in the high accelerator operation amount, a high acceleration feeling intended by the driver can be obtained in the high accelerator operation amount region.

It should be noted that, since a condition of l ₀ ≧ l _H indicating the driver's willingness to accelerate is added, even if there is no direct correspondence between the absolute accelerator operation amount 1 and the throttle opening θ, the accelerator operation does not feel uncomfortable.

The map drop control of the area control characteristic map is performed on condition that the slip ratio S is S> S ₁ and FLAG · A = 0. After being dropped, the slip ratio is once S ≦
Also it becomes S _1, or satisfies the map up condition, until the slip ratio S exceeds newly set slip ratio S ₁ or S ₂ in order to lower the area control characteristic map is held as it is, the driving wheel slip Even after the avoidance, there is no immediate return to the previous drive force level at which the drive wheel slip occurred, and re-slip is prevented.

Further, as to fall further maps When newly exceeds the set slip ratio S _1, since for the generation of the driving wheel slip is controlled only in a direction to reduce the driving force to reduce the throttle opening theta, drive There is no hunting that accompanies the increase or decrease in force, and jerk vibration is prevented.

Even if there is no direct correspondence between 1 and the throttle opening θ,
There is no discomfort in accelerator operation.

The map drop control of the area control characteristic map is performed on condition that the slip ratio S is S> S ₁ and FLAG · A = 0. After being dropped, the slip ratio is once S ≦
Also it becomes S _1, or satisfies the map up condition, until the slip ratio S exceeds newly set slip ratio S ₁ or S ₂ in order to lower the area control characteristic map is held as it is, the driving wheel slip Even after the avoidance, there is no immediate return to the previous drive force level at which the drive wheel slip occurred, and re-slip is prevented.

Further, as to fall further maps When newly exceeds the set slip ratio S _1, since for the generation of the driving wheel slip is controlled only in a direction to reduce the driving force to reduce the throttle opening theta, drive There is no hunting associated with the increase or decrease in force, and jerk vibration is prevented.

If a slip occurs in the process of opening the throttle opening based on map up control, it is estimated that the current slip occurs due to the throttle opening about 600 msec before taking into account the engine response delay, and the opening is used as a reference. As the map drop control is performed to drop one more sheet (two sheets are dropped when the slip is excessive), it is possible to obtain the throttle opening in conformity with the current road surface friction coefficient without inducing acceleration failure or re-slip.

When shifting up to the high-speed gear position, the map drop control that shifts to the lower control characteristic map is prohibited regardless of the magnitude of the slip ratio S. Therefore, when the shift-up is performed, the drive simply occurs due to an apparent slip. There is no reduction in force, and the feeling of poor acceleration due to insufficient driving force during upshifting is eliminated.

In particular, this prohibition of map dropping cannot be recognized by the driver because the driver cannot recognize when to shift up.
This is useful for A / T vehicles.

Next, a second embodiment will be described with reference to FIG.

Only the map drop prohibiting processing at the time of upshifting different from the first embodiment will be described with reference to the flowchart of FIG. 91.

In step 270 engine rotational speed N _E read, whether negative difference .DELTA.N _E of the engine rotational speed N _E read this step 271 and the first control cycle before the engine rotational speed N _E o is determined, step 272 Then, it is judged whether the difference ΔV _R between the rear wheel speed V _R read this time and the rear wheel speed V _R o one control cycle before is positive, and when ΔN _E <0 and ΔV _R > 0, that is, At the time of upshifting, the routine proceeds to step 273, where the map drop prohibition flag UPFLAG is set to "1", and at step 274 the map drop prohibit time timer UPTAMR is cleared.

When the predetermined time K has not elapsed from the upshift and the map drop prohibition flag UPFLAG = 1, the process proceeds from step 275 to step 276, and it is determined whether UPTMR has passed the predetermined time K (for example, K = 1 sec). If it has not elapsed (UPTMR <K), UPTMR is incremented (step 277).

The flow from step 275 to step 277 is repeated, and when UPTMR = K in step 276, the flow proceeds to step 278 to release the map drop prohibition and UPTMR and
Clear UPFLAG, and proceed to the map drop processing after step 120.

If it is not during an upshift, step 270 →
The process proceeds from step 271 (→ step 272) to step 275, and the map drop processing of step 120 and subsequent steps is directly performed without any inhibition of map drop.

Therefore, in this second embodiment, even if the electric shift signal cannot be received, the shift up can be determined under the condition that the engine speed is decreasing and the driving wheel speed is increasing. This is useful in the case of A / T vehicles, etc., in which shift control is performed by hydraulic control.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and the present invention can be applied even if there is a design change or the like within a range not departing from the gist of the present invention. included.

For example, in determining the map drop prohibition time K, it is determined by other factors closely related to the degree of decrease in engine speed during upshift, such as gear position, engine speed, engine supercharging pressure, and engine intake negative pressure. It may be done.

Further, in the embodiment, an example in which a plurality of area control characteristic maps having an upper limit and a lower limit are set is shown, but a linear control characteristic map such as a straight line, a polygonal line or a curve may be used, or an area control characteristic map having only an upper limit Good.

Further, in the map drop control, the number of maps to be dropped may be determined according to the degree of increase in the slip ratio, taking into consideration the time change rate of the slip ratio.

Further, although one characteristic is shown as the ΔL-Δθ characteristic in the embodiment, for example, when the map # 0 is selected, Δθ based on the characteristic of the solid line is added when the characteristic shown by the dotted line in FIG. 4 is added. When the maps # 1 to # 7 are selected, Δθ based on the characteristic of the dotted line may be set. In this case, the control gain of the throttle opening with respect to the absolute accelerator operation amount is set to the traveling road surface. The situation can be dealt with and the drive wheel slip can be prevented.

Further, when the slip ratio exceeds a new set value, the throttle valve may be unconditionally fully closed to avoid the drive wheel slip early.

(Effects of the Invention) As described above, in the vehicle driving force control device of the present invention, basically, each time the slip ratio exceeds the set slip ratio, the selected control characteristic map is selected. Select a lower control characteristic map that has a lower throttle opening increase ratio with respect to the accelerator operation amount, but if a shift-up state is detected, the slip ratio is set to the set slip ratio within a predetermined time from the shift-up detection. Even if it exceeds, a map selecting means for prohibiting the transition to the lower control characteristic map, a target throttle opening value is obtained by the control characteristic map selected by the map selecting means and the accelerator operation amount, A device provided with a target throttle opening value setting means for fully closing the target throttle opening value for a predetermined time after the shift up is detected during a shift up. Therefore, the effects listed below can be achieved.

(1) Since a plurality of relations of the throttle opening degree with respect to the accelerator operation amount are set as the control characteristic map, the throttle opening degree is not controlled regardless of the accelerator operation amount and it is possible to eliminate the feeling of strangeness in accelerator operation.

(2) In the map drop control when a slip occurs, the drive wheel slip is effectively prevented because the map lower than the selected control characteristic map is selected every time the slip ratio exceeds the set slip ratio. In addition, it is possible to prevent re-slip and control hunting.

(3) At the time of shift-up, even if the slip ratio exceeds the set slip ratio during the predetermined time after the shift-up detection, the shift to the lower control characteristic map is prohibited, and the throttle valve is opened for the predetermined time after the shift-up detection. Since it is fully closed, it is possible to achieve both the suppression of slippage due to the gear ratio change at the time of shift-up and the assurance of acceleration after the shift-up.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to the claims showing the vehicle driving force control device of the present invention, FIG. 2 is an overall view showing the driving force control device of the first embodiment of the present invention, and FIG. 3 is a throttle of the first embodiment device. FIG. 5 is a region control characteristic map diagram set in the valve control circuit, FIG. 4 is a characteristic diagram of a relation between relative accelerator operation amount and throttle opening change amount set in the throttle valve control circuit of the first embodiment device, FIG. FIG. 1 is a flow chart showing a main routine of control operation in the throttle valve control circuit of the first embodiment,
FIG. 6 is a flowchart showing a control operation subroutine in the throttle valve control circuit of the first embodiment, FIG. 7 is a slip ratio threshold characteristic diagram in the first embodiment, and FIG. 8 is the first embodiment. FIG. 9 is a time chart diagram showing the drive control operation at the time of starting in the example device, and FIG. 9 is a flow chart diagram showing the main parts in the second embodiment. a: driving wheel speed detecting means b: vehicle speed detecting means c: slip ratio calculating means d: accelerator operation amount detecting means e: upshift detecting means f: actual throttle opening value detecting means g: Map setting means h …… Map selecting means i …… Target throttle opening value setting means j …… Throttle actuator k …… Throttle valve opening / closing control means

Front page continuation (72) Inventor Toru Iwata 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (56) Reference JP-A-63-113131 (JP, A)

Claims (3)

[Claims] 1. A slip ratio calculating means for calculating a slip ratio between a tire and a road surface based on a wheel speed obtained from a drive wheel speed detecting means and a vehicle body speed obtained from a vehicle body speed detecting means, and an accelerator operation amount for an accelerator operator. Accelerator operation amount detecting means for detecting, upshift detecting means for detecting an upshift state, actual throttle opening value detecting means for detecting the actual throttle opening value of the throttle valve, and throttle opening amount for the accelerator operation amount. Map setting means for setting a plurality of relationships as a control characteristic map, and basically, each time the slip ratio exceeds the set slip ratio, the throttle opening for the accelerator operation amount is selected from the selected control characteristic map. Select a lower control characteristic map with a lower increase ratio, but if a shift-up condition is detected, A map selecting means for prohibiting the shift to the above-mentioned lower control characteristic map even if the slip rate exceeds the set slip rate in a predetermined time after the detection of the start-up, and the control characteristic map selected by the map selecting means. A target throttle opening value is set based on the accelerator operation amount, and at the time of shift-up, a target throttle opening value setting means for fully closing the target throttle opening value for a predetermined time from shift-up detection, and the actual throttle opening A vehicle driving force control device comprising: a throttle valve opening / closing control unit that outputs a control signal that causes a value to match the target throttle opening value to a throttle actuator. 2. The shift-up detecting means is means for detecting a gear position of a transmission and detecting a shift-up state when the detected gear position is switched to a high speed side. Vehicle driving force control device. 3. The shift-up detecting means detects an engine speed and a drive wheel speed, and detects a shift-up state by the engine speed decreasing direction and the drive wheel speed increasing direction. The vehicle driving force control device according to claim 1, which is a means.