JP2000027673A - Vehicle drive force control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a desirable feeling of acceleration, irrespective of variation in gradient of a road surface in a transient zone between a flat surface road and a slope. SOLUTION: A computing means 3 computes a target drive force of a vehicle on a flat surface road, as a normal target drive force, from an accelerator manipulating degree and a vehicle speed which are detected, and a computing means 5 computes a target drive force for the vehicle, for a slope from a detected weight gradient resistance and in accordance with the normal target drive force. In accordance with thus computed target drive force for the slope, an adjusting means 6 adjusts variation in thus computed target drive force for the slope, and thus adjusted target drive force for the slope is computed as a final target drive force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle driving force control device, and more particularly to a vehicle driving force control device capable of obtaining a vehicle driving force corresponding to a gradient of a traveling road.

[0002]

2. Description of the Related Art Conventionally, for example, there is a type in which a shift characteristic is changed and controlled so as to obtain an optimum characteristic corresponding to a gradient of a traveling road (Japanese Patent Publication No. 59-8698,
See JP-A-8-219242). These are used to determine whether the road is a flat road or an uphill road and to switch the shift map, or to continuously correct the speed ratio according to the gradient of the road surface when traveling uphill so that the acceleration is not slowed down by the gradient. .

[0003]

However, when the driving force characteristic is changed from the driving force characteristic on a flat road to the driving force characteristic corresponding to an ascending slope, it is desired to perform the gear ratio control regardless of the amount of change in the road surface gradient. Feeling of acceleration cannot be obtained.

[0004] For example, when approaching an uphill road from a flat road, it is conceivable to increase the driving force by a fixed amount so that the feeling of acceleration is not dulled. In this case, if the switching speed of the driving force when the road surface gradient is changed is adapted so as to correspond to the steep ascending road, the increase in the driving force is unsatisfactory when approaching a gentle uphill road. It feels like lack of acceleration. Conversely, if the switching speed of the driving force when the road surface gradient is changed is adapted to correspond to a gentle uphill road, when the vehicle approaches a steep uphill road, the increase in the driving force becomes excessive. It is felt as a thing and a sense of tension is generated.

[0005] Therefore, the present invention adjusts the speed of change (= the amount of change per unit time) of the target driving force in accordance with the amount of change in the road surface gradient when the vehicle is approaching a slope from a flat road. An object of the present invention is to obtain a desired feeling of acceleration irrespective of a road surface gradient when approaching a road.

[0006]

According to a first aspect of the present invention, as shown in FIG. 14, a means 1 for detecting an accelerator operation amount, a means 2 for detecting a vehicle speed, and the detected accelerator operation amount and vehicle Means 3 for calculating the target driving force of the vehicle on a flat road according to the speed as a normal target driving force, means 4 for detecting a weight gradient resistance (force), and the detected weight gradient resistance and the normal target driving force. Means 5 for calculating the target driving force of the vehicle according to the force as the target driving force corresponding to the gradient, and adjusting the changing speed of the target driving force corresponding to the gradient in accordance with the calculated change in the target driving force corresponding to the gradient. There are provided means 6 for calculating the target driving force corresponding to the gradient as the final target driving force, and means 7 for realizing the final target driving force.

According to a second aspect of the present invention, in the first aspect, the adjustment of the changing speed of the target driving force corresponding to the gradient is changed to a side where the target driving force corresponding to the gradient is increased and the change is made in a region where the amount of the change is large. The ratio of the change speed of the final target driving force to the amount is reduced.

According to a third aspect of the present invention, in the first aspect, the adjustment of the changing speed of the gradient corresponding target driving force is performed when the change of the gradient corresponding target driving force is within a predetermined range near zero.
The change speed of the final target driving force is set to zero.

In a fourth aspect, in any one of the first to third aspects, the gradient corresponding target driving force calculating means 5 sets the weight gradient resistance RFORCE to 100% and corrects the driving force by a percentage smaller than 100%. Means for calculating the amount ΔRFORCE, and calculating the calculated driving force correction amount ΔRFORCE with the normal target driving force tTd. The value added to n is the target driving force corresponding to the gradient tTd c means.

In a fifth aspect, in the fourth aspect, the driving force correction amount ΔRFORCE is 30% to 70% of the magnitude of the weight gradient resistance RFORCE.

According to a sixth aspect, in the fourth aspect, the ratio of the driving force correction amount ΔRFORCE to the weight gradient resistance RFORCE is a value that decreases as the weight gradient resistance RFORCE increases.

According to a seventh aspect of the present invention, any one of the first to third aspects is provided.
In one aspect of the present invention, the slope-dependent target driving force calculating means is used.
Step 5 is a predetermined weight gradient resistance RFORCE that is not a flat road S
Percentage value less than this as 100%
Normal target driving force tTd Target drive equivalent to the value added to n
The reference target driving force tTd Preset as up
Means, the detected weight gradient resistance RFORCE and the predetermined
Weight gradient resistance RFORCE Method to calculate interpolation coefficient β0 from S
Step and the gradient corresponding reference target using the interpolation coefficient β0.
Driving force tTd up and the normal target driving force tTd Interpolation calculation with n
The value obtained is the target driving force tTd corresponding to the slope. Means of calculating as c
Consists of

In an eighth aspect, as shown in FIG. 15, a means 1 for detecting an accelerator operation amount, a means 2 for detecting a vehicle speed, and a flat surface corresponding to the detected accelerator operation amount and vehicle speed. The target driving force of the vehicle on the road is the normal target driving force.
tTd means 3 for calculating as n, and a predetermined weight gradient resistance RFORCE which is not a flat road The normal target driving force tTd The target driving force corresponding to the value added to n is a reference target driving force tT corresponding to the gradient.
d means 141 for setting as up, means 4 for detecting the weight gradient resistance (force), and the detected weight gradient resistance RFORCE
And the predetermined weight gradient resistance RFORCE Interpolation coefficient β0 from S
A means 142 for adjusting the rate of change of the interpolation coefficient in accordance with the change in the calculated interpolation coefficient β0, and calculating the adjusted interpolation coefficient as the final interpolation coefficient β.
And the gradient corresponding reference target driving force tTd using the final interpolation coefficient β. up and the normal target driving force tTd a means 144 for calculating a value obtained by interpolation between n and the final target driving force tTd,
Means 7 for realizing the final target driving force.

According to a ninth aspect, in the eighth aspect, the adjustment of the changing speed of the interpolation coefficient is changed to a side where the interpolation coefficient β0 is increased and the final interpolation for the changed amount is performed in a region where the variation is large. The purpose is to reduce the rate of the coefficient change rate Δβ.

In a tenth aspect based on the eighth aspect, the adjustment of the change rate of the interpolation coefficient is performed when the change rate of the interpolation coefficient is within a predetermined range near zero. It is to make it zero.

According to an eleventh aspect of the present invention, in any one of the first to tenth aspects, the means 4 for detecting the weight gradient resistance includes a means for detecting an absolute position of the vehicle, and a vehicle based on the detected value. And means for calculating the weight gradient resistance from the estimated road gradient.

In a twelfth aspect of the present invention, in any one of the first to tenth aspects, the means 4 for detecting the weight gradient resistance comprises means for calculating a driving shaft rotational force, and means for calculating flatness according to the vehicle speed. Means for calculating a reference running resistance on a road as a reference running resistance; means for detecting the acceleration of the vehicle; means for estimating the acceleration resistance (force) of the vehicle based on the detected acceleration; Means for estimating, as the weight gradient resistance, a value obtained by subtracting the reference running resistance and the acceleration resistance from the obtained drive shaft rotational force.

[0018]

According to the first aspect of the present invention, the speed of change of the target driving force is adjusted according to the change of the target driving force (corresponding to the change of the road surface gradient). A desired acceleration feeling can be obtained regardless of the road gradient at the time.

According to the second aspect of the present invention, the target driving force changes to a side where the target driving force corresponding to the gradient becomes large and the amount of the change is large. According to the ninth aspect of the present invention, the rate of change of the final target driving force with respect to the amount is reduced, and the interpolation coefficient changes to a larger side and the change is large. (I.e., when the road surface gradient is large when approaching a gradient road in both inventions, the rate of change of the final target driving force is suppressed). The driving force is suddenly corrected so that the driver does not feel the rushing feeling.

According to the third and tenth aspects of the present invention, no exaggerated driving force correction is performed for a minute change in the road surface gradient that the driver does not feel, and the gradient is estimated (or estimated). Even if the target driving force changes minutely due to minute gradient estimation variation caused by noise or the like in the case of measurement, it is possible to suppress a change in the final target driving force.

In the fourth invention, the weight gradient resistance is set to 100
To calculate the driving force correction amount ΔRFORCE of a percentage less than the percentage, it is only necessary to multiply the weight gradient resistance by a coefficient less than one. In other words, the target driving force on a flat road can be obtained simply by holding one coefficient for the weight gradient resistance.
(Normal target driving force) can be converted into a target driving force corresponding to the gradient, and therefore, according to the fourth invention, it is not necessary to have a different target map such as a high output mode corresponding to the gradient, which is different from the conventional one, unlike the conventional device. In addition, it is possible to prevent the ROM capacity from being enlarged. Further, characteristic tuning by changing the gradient resistance coefficient can be easily performed.

According to the fifth aspect of the present invention, the driving force correction can be assisted with the most uncomfortable feeling when climbing a hill or the like.
You can always get a natural feeling of acceleration.

According to the sixth aspect of the present invention, a natural feeling of acceleration can be produced while always reducing the driver's discomfort regardless of how the gradient changes.

According to the seventh aspect of the present invention, the means for presetting the reference target driving force corresponding to the gradient is provided, so that it is possible to easily incorporate various constraint conditions. For example, it is possible to set the reference target driving force corresponding to the gradient so that the driving force cannot be actually output due to the output torque characteristics of the mounted engine. In addition, for example, other driving ranges (for example, sport mode)
By setting the reference target driving force corresponding to the gradient smaller than the target driving force in the above, it is possible to avoid acceleration or deceleration arbitrarily regardless of the driver's intention when switching to the sport mode. Alternatively, it is also possible to make a setting that always changes to the acceleration side as expected by the driver.

According to the eighth aspect, since the changing speed of the interpolation coefficient used for the interpolation calculation is adjusted instead of adjusting the changing speed of the target driving force, modularization of each means is simplified, and the driving force control can be performed easily. When the processing is performed by a controller having a CPU, the processing load on the CPU can be reduced. For example, when an external sensor for detecting the weight gradient resistance is used, it is often the case that another CPU process is externally performed in order to transmit the sensor signal to the CPU that controls the driving force. According to the eighth aspect of the present invention, from the calculation of the interpolation coefficient to the adjustment of the interpolation coefficient, the signal processing CP of the external sensor is used.
It becomes possible to process in U.

According to the eleventh aspect, the road gradient at the position where the vehicle exists can be estimated from the map information and the absolute position information from satellites and the like, so that the driving due to the change in the vehicle state such as tire puncture or aging deterioration can be achieved. The road gradient can always be detected accurately without being affected by changes in the force characteristics.
In addition, since it is possible to estimate the gradient not only of the existing road, but also of the road that is going ahead, it is possible to correct the driving force by pre-reading the gradient, making the driver more responsive. Good driving force correction becomes possible.

According to the twelfth aspect, since it is not necessary to provide a new sensor for detecting the weight gradient resistance, the weight gradient resistance can be estimated at very low cost.

[0028]

FIG. 1 is a block diagram of the entire control system.

The output of the engine 101 is transmitted to driving wheels (not shown) via an automatic transmission 103 with a built-in torque converter. The automatic transmission here is a stepped automatic transmission using a planetary gear and a clutch member. The present invention is not limited to a stepped transmission, and can be applied to a continuously variable transmission such as a V-belt type or a toroidal type.

In the intake passage of the engine 101, a so-called electronic control throttle device 102 for opening and closing a throttle valve by a motor or the like is interposed, and the amount of air taken into the engine 101 is adjusted by the throttle valve opening. The output torque of the engine is controlled.

To drive the electronic control throttle device 102, a throttle control module (hereinafter referred to as TC
M) 51 is provided. In the TCM51, which receives a throttle valve opening command from a power train control module (hereinafter referred to as PCM) 50, the throttle valve opening command is converted to a motor drive voltage and output to the motor, and the actual throttle valve opening is set to PCM50. The motor drive voltage (throttle valve opening) is feedback-controlled so as to match the opening command from the ECU.

An accelerator operation amount (accelerator pedal depression amount) sensor 105 receives an accelerator operation amount signal, a brake operation signal from a brake operation switch 106, a select range signal from an automatic transmission range selection lever 107, and the like. In the PCM 50, based on these signals, engine control (for example, mainly control of the fuel supply amount to the engine 101 and ignition timing), automatic transmission control (gear position control for the automatic transmission 103, hydraulic control), braking force Each control (control of brake hydraulic pressure for each wheel to the brake actuator 104) is performed.

On the other hand, reference numeral 111 denotes a camera for taking an image of the situation in front of the vehicle as an image.
The information is processed as obstacle information or the like and transmitted to the external environment information processing module 52.

Reference numeral 113 denotes a GPS antenna 113 for receiving a signal from a satellite. Information from the satellite is transmitted to the position information processing device 54 in order to grasp the current position of the vehicle. Map information incorporating geographical attributes and road information in advance
The position information processing device 54 stored as a recording medium such as a CD-ROM collects this information and the signal from the GPS antenna 113 to collect information on the area where the current position is present, etc. Send to

The external environment information processing module 52 appropriately summarizes the current vehicle environment and transmits it to the PCM 50. The PCM 50 receives this signal and controls the output of the engine 101 and the shift of the automatic transmission 103. I do. Conversely, PCM50 is
The output torque information of the engine 101, the gear position information of the automatic transmission 103, the signal states from the accelerator opening sensor 105, the brake operation switch 106, and the like are transmitted to the external environment information processing module 52. In the external environment information processing module 52,
In response to this signal, the accuracy of determining the external environment may be increased, or the mental state of the driver may be estimated.

Conventionally, there is a conventional one in which, for example, a shift characteristic is changed and controlled so as to obtain an optimum characteristic according to the gradient of the traveling road.

However, in the case where the driving force characteristic on a flat road is changed to the driving force characteristic corresponding to an ascending gradient, a desired feeling of acceleration can be obtained by performing the speed ratio control regardless of the amount of change in the road surface gradient. Absent. For example, when approaching an uphill road from a flat road, it is conceivable to increase and correct the driving force by a certain amount so that the feeling of acceleration is not dulled. In this case, if the switching speed of the driving force when the road surface gradient is changed is adapted so as to correspond to the steep ascending road, the increase in the driving force is unsatisfactory when approaching a gentle uphill road. It feels like lack of acceleration. Conversely, if the switching speed of the driving force when the road surface gradient is changed is adapted to correspond to a gentle uphill road, when the vehicle approaches a steep uphill road, the increase in the driving force becomes excessive. It is felt as a thing and a sense of tension is generated.

In order to cope with this, in the first embodiment of the present invention, when the driving force characteristic is changed from the driving force characteristic on a flat road to the driving force characteristic corresponding to an ascending slope, the change in the target driving force in response to the change in the road surface gradient. Adjust the speed (= change amount per unit time).

This control performed by the PCM 50 will be described with reference to the block diagram of FIG.

The normal target driving force setting means 12 to which the accelerator operation amount APO detected by the accelerator operation amount sensor 105 and the vehicle speed VSP detected by the vehicle speed detection means 11 are inputted, according to these values. The target value of the vehicle driving force when traveling on a flat road is the normal target driving force tTd. Set as n.

The gradient corresponding target driving force calculating means 15 includes a driving force correction amount calculating means (comprising a multiplying means) 16 and a driving force correcting means (comprising an adding means) 17. The driving force correction amount calculating means 16 to which the weight gradient resistance RFORCE detected by the weight gradient resistance detecting means 14 is input,
The driving force correction amount ΔRFORCE (= α × RFORCE) is obtained by multiplying the CE by the gradient resistance coefficient α (where 0 <α <1), and the value of the correction amount ΔRFORCE is calculated by the driving force correction means 17 as described above. Target driving force tTd n, the target driving force corresponding to the gradient tTd c (= tTd n + ΔRFORCE) is calculated.

A feeling of acceleration that the driver can satisfy on a flat road
Normal target driving force tTd n, also uphill road
Drive to give the driver a satisfactory feeling of acceleration
By calculating the force correction amount ΔRFORCE,
A comfortable feeling of acceleration is always obtained regardless of the road or uphill
It is.

In this case, the target driving force on the flat road can be converted into the target driving force corresponding to the gradient only by holding one gradient resistance coefficient α with respect to the weight gradient resistance RFORCE. It is not necessary to have an unusual target map such as a certain high output mode, so that the ROM capacity can be prevented from being enlarged. Further, characteristic tuning by changing the gradient resistance coefficient α can be easily performed.

The target driving force tT corresponding to the gradient thus obtained.
d c is converted into the final target driving force tTd via the target driving force change speed adjusting means 20.

The target driving force change speed adjusting means 20 comprises a target driving force change amount setting means 21, an adding means 22, and a delay calculating means 23.

The target driving force corresponding to the gradient tTd The target driving force change amount setting means 21 to which c is input sets a target driving force change amount per unit time (a change amount per 10 msec when this block is processed every 10 msec) ΔTd. For example, the final target driving force obtained 10 msec before is tTd _-1
Then, the target driving force tTd obtained this time c and this t
By searching a predetermined map from the deviation from Td- ₁ (change in target driving force), a change amount ΔTd per unit time of the target driving force is obtained.

In the adding means 22, the value of ΔTd is set to tT of the previous value.
By being added to d- ₁ , the final target driving force tTd (= tTd- ₁ + .DELTA.Td), which is the current value, is obtained. Note that the delay calculating means 23 becomes z ^-1 when expressed in a discrete time system, and tT
By multiplying d by this z ⁻¹ , one sample period before (10 mse
cT) which is the value of tTd _-1 (= tTd × z ^-1 ) is obtained.

As shown in the drawing, the characteristic of ΔTd is represented by a deviation (tTd) shown on the horizontal axis. c−tTd ₋₁ ) is a value that is proportional to the deviation in a range within a predetermined value, and when the deviation exceeds a predetermined value, the ratio of the variation ΔTd per unit time of the target driving force to the deviation is reduced. The amount of change ΔTd per unit time of the target driving force is calculated by using the above-mentioned deviation tTd which is a change in the target driving force. c-t
By setting it in accordance with Td _-1 (this deviation represents the amount of change in the road surface gradient when approaching a slope road from a flat road), the switching speed of the driving force when approaching a slope road from a flat road can be changed. Adjust.

FIG. 3 is a flowchart configured corresponding to the block diagram of FIG.

Although a portion that overlaps with that described in FIG. 2 may appear, FIG.
Execute every 10 msec.

In step 1, the accelerator operation amount APO, the vehicle
Read both speed VSP and weight gradient resistance RFORCE
Normal target drive according to accelerator operation amount APO and vehicle speed VSP
Force tTd Set n in step 2. Where normal eyes
Target drive force tTd n is the vehicle driving force when driving on a flat road
It is a standard value.

In step 3, the driving force correction amount ΔRFORCE (= α × RFORCE) is obtained by multiplying the weight gradient resistance RFORCE by the gradient resistance coefficient α (where 0 <α <1). Normal target driving force tTd By adding to n, the target driving force corresponding to the gradient tTd c (= tTd n +
ΔRFORCE).

In step 5, this Td calculated this time A predetermined map is searched from the deviation between c and the previous value of the final target driving force tTd- ₁ to determine a change amount ΔTd per unit time of the target driving force, and this value ΔTd is calculated in step 6 as the final target driving force. The final target driving force tTd (= tTd _-1 + ΔTd) is obtained by adding the value to tTd _-1 which is the previous value of.

As described above, in the first embodiment of the present invention,
Deviation Td, which is a change in the target driving force when changing from the target driving force on a flat road (normal target driving force) to the target driving force corresponding to the ascending slope. Since the amount of change ΔTd (change speed of the target driving force) of the target driving force per unit time is adjusted in accordance with c−tTd ₋₁ (corresponding to the change of the road surface gradient), the road is changed from a flat road to a gradient road. Regardless of the road gradient when approaching,
The desired acceleration can be obtained.

In a region where the gradient is large when the vehicle is going uphill from a flat road, the target driving force corresponding to the gradient changes to a side where the target driving force increases, and the amount of the change is large. Since the rate of change of the force is reduced (that is, the speed of change of the final target driving force is suppressed when the road surface gradient is large when approaching a sloping road), for example, the moment when the vehicle approaches a steep uphill road The driving force is suddenly corrected so that the driver does not feel the rushing feeling.

FIG. 4 shows the gradient resistance coefficient calculating means 31 of the second embodiment.

In the first embodiment, the gradient resistance coefficient α is a constant value, whereas in the second embodiment, the gradient resistance coefficient α is a function of the weight gradient resistance RFORCE, that is, the weight gradient resistance RF.
It is made smaller as ORCE becomes larger.

Here, as the weight gradient resistance increases, α
The reason for reducing the value is that the driver recognizes the gradient more strongly as the weight gradient resistance increases. In other words, when the gradient is gentle, the driver does not notice the gradient very much, so the accelerator operation amount is not much different from that on a flat road. Tends to be. On the other hand, as the gradient increases, the driver recognizes the gradient and consciously depresses the accelerator pedal deeply, so even if the ratio of the driving force correction amount ΔRFORCE to the weight gradient resistance is smaller than the gentle gradient, acceleration I do not feel shortage. Therefore, if α is given so that the ratio of the driving force correction amount ΔRFORCE to the weight gradient resistance becomes smaller as the weight gradient resistance increases, the discomfort felt by the driver can be reduced regardless of how the gradient changes. You can always produce a natural feeling of acceleration.

The reason why the gradient resistance coefficient α is changed between 30% and 70% is that the driving force correction can be assisted most comfortably when traveling uphill, for example, when the gradient resistance coefficient α is 30% of the weight gradient resistance.
This is because the range is about 70%. As a result, not only a lack of acceleration or a sense of tension is not felt when traveling uphill, but also a natural feeling of acceleration is always obtained.

FIGS. 5 and 6 show a third embodiment, which replaces FIGS. 2 and 3 of the first embodiment, respectively. FIG.
2, the same parts as those in FIG. 2 are denoted by the same reference numerals, and in FIG. 6, the same parts as those in FIG. 3 are denoted by the same step numbers.

5 is different from FIG. 2 mainly in that it is different from FIG. 2 in the content of the gradient corresponding target driving force calculating means 41, which is the gradient corresponding reference target driving force setting means.
42, a dividing means 43, and a target driving force interpolation calculating means 44.

Among them, the gradient-based reference target driving force setting means
In step 42, a predetermined value is obtained from the accelerator operation amount APO and the vehicle speed VSP.
By searching the map, the reference target driving force corresponding to the slope
tTd up is required. Here, the slope-based reference target driving force t
Td Up means a predetermined weight gradient resistance RFORCE that is not a flat road
Set S to 100% and precede any lower value
Normal target driving force tTd target drive equivalent to the value added to n
Power, specifically the normal target driving force tTd to n
And

[0063]

[Equation 1] tTd up = tTd n + α × RFORCE It is predetermined so as to be S.

On the other hand, in the dividing means 43, the weight gradient resistance RFOR
CE (detected value) is set to the predetermined weight gradient resistance RFORCE By dividing by S,

[0065]

[Equation 2] β0 = RFORCE / RFORCE The interpolation coefficient β0 (dimensionless number) is calculated by the formula of S, and the target driving force interpolation calculation means 44 uses this interpolation coefficient β0 to calculate

[0066]

[Equation 3] tTd c = β0 × tTd up + (1-β0) × tTd The target driving force corresponding to the gradient tTd is calculated by the interpolation formula of n c is required.

For example, RFORCE = RFORCE In the case of S, β0 = 1 from equation (2), and tTd from equation (3) c = tTd up
Becomes

The target driving force tT corresponding to the gradient thus calculated.
d c is tTd in FIG. Similarly to c, it is converted to the final target driving force tTd via the target driving force change speed adjusting means 20.

FIG. 6 is a flowchart configured corresponding to FIG. In FIG. 6, steps 11, 12, and 13 are different from FIG.

Here also, there is a portion that overlaps with that described with reference to FIG. 5, but it will be described anyway. In step 11, the normal target driving force tTd n, gradient resistance coefficient α, reference weight gradient resistance RFORCE Using S, the slope-corresponding reference target driving force tTd is calculated by the above equation (1). Ask for up.

In step 12, the weight gradient resistance RFORCE (detected value) and the reference weight gradient resistance RFORCE The interpolation coefficient β0 is calculated from S by the above equation (2), and the gradient corresponding target driving force tTd is calculated in step 13 using the interpolation coefficient β0 by the above equation (3). Find c.

As described above, in the third embodiment, the gradient-based reference target driving force tTd Since there is a means for setting up in advance, it is possible to easily make up various constraint conditions. For example, the reference target driving force tTd corresponding to the gradient is set so that the driving force cannot be actually output due to the output torque characteristic of the mounted engine. It is possible to set up. In addition, for example, the reference target driving force tTd that is smaller than the target driving force in another driving range (for example, the sports mode) and that corresponds to the gradient. By setting up, it is possible to avoid acceleration or deceleration without permission regardless of the driver's intention when switching to the sports mode. Alternatively, it is also possible to make a setting that always changes to the acceleration side as expected by the driver.

FIGS. 7 and 8 show a fourth embodiment, which replaces FIGS. 5 and 6 of the third embodiment, respectively. FIG.
5, the same parts as those in FIG. 5 are denoted by the same reference numerals, and in FIG. 8, the same parts as those in FIG. 6 are denoted by the same step numbers.

As shown in FIG. 7, in the fourth embodiment, an interpolation coefficient changing speed adjusting means 60 is provided in place of the target driving force changing speed adjusting means 20 in FIG. The means 60 includes an interpolation coefficient change amount setting means 61 and an adding means.
62, a delay operation means 63.

The interpolating coefficient change amount setting means 61 to which the interpolating coefficient β0 is input is used to change the interpolating coefficient per unit time (10 msec when this block is processed every 10 msec).
The hit change amount Δβ is set. For example, if the final interpolation coefficients obtained before 10msec and beta _-1, (change of the interpolation coefficients) deviation between the interpolation coefficients β0 Toko of beta _-1 determined time
, A change amount Δβ per predetermined time of the interpolation coefficient is calculated.

The adding means 62 adds the change amount Δβ per predetermined time set in this way to the previous value β ₋₁ , so that the final interpolation coefficient β (= β ₋₁ +
Δβ) is obtained.

As shown in the figure, the characteristic of Δβ is that the deviation (β ₀ −β ₋₁ ) shown on the horizontal axis is proportional to the deviation in a range within a predetermined value. This is a value obtained by reducing the ratio of the variation Δβ per unit time of the interpolation coefficient. Also in this case, the amount of change Δβ per unit time of the interpolation coefficient is calculated by using the above-mentioned deviation β0−β
_-1 (this deviation represents a change in gradient when approaching a flat road to a gradient road), and as a result, the speed of change of the driving force is adjusted similarly to the third embodiment. It is.

On the other hand, the target driving force interpolation calculating means 66 of the gradient corresponding target driving force calculating means 65 uses the final interpolation coefficient β thus obtained,

[0079]

[Equation 4] tTd = β × tTd up + (1-β) × tTd The final target driving force tTd is obtained from the interpolation formula for n.

FIG. 8 is a flowchart corresponding to the block diagram of FIG.

FIG. 8 differs from FIG. 6 of the third embodiment in steps 21, 22, and 23.

Here also, there is a portion that overlaps with that described with reference to FIG. 7, but it will be described anyway. In step 21, the interpolation coefficient β0 obtained this time and β ₋ which is the final interpolation coefficient obtained 10 msec ago. By searching a predetermined map from a deviation from ₁ (change of the interpolation coefficient), a change amount Δβ per unit time of the interpolation coefficient is obtained. This Δβ is calculated in step 2
The final interpolation coefficient β (= β _-1 + Δβ), which is the current value, is obtained by adding to the previous value β ₋₁ in step 2, and the final interpolation coefficient β is used in step 23 to obtain the above equation (4). To calculate the final target driving force tTd.

As described above, in the fourth embodiment, instead of adjusting the changing speed of the target driving force, the normal target driving force tTd n
And slope-based reference target driving force tTd Since the configuration is such that the rate of change of the interpolation coefficient β used for the interpolation calculation with up is adjusted, modularization of each means is simplified, and when driving force control is performed by a control module (PCM50) equipped with a CPU, The processing load on the CPU can be reduced. For example, when an external sensor for detecting the weight gradient resistance is used, the sensor signal is transmitted to a CPU for controlling the driving force, so that another CPU process is often performed externally. According to the fourth embodiment, the means 43 and 60 for performing from the calculation of the interpolation coefficient to the adjustment of the interpolation coefficient can be processed by the signal processing CPU of the external sensor.

In the configuration shown in FIG. 2, since the target driving force change speed adjusting means 20 is connected in series, the update speed of the target driving force is determined by the processing speed of the means 20, whereas the processing speed of the target driving force changing speed adjusting means 20 is determined. Since the dividing means 43 and the interpolation coefficient switching speed adjusting means 60 are connected in parallel to the other means 12, 42, 66, the processing speed of the means 43, 60 is reduced by the means 12, 42, 66.
Can be set separately from the processing speed.

FIG. 9 shows a fifth embodiment, which shows a method of estimating the gradient of a road surface from map data including altitude.

In the figure, it is assumed that the gradient of the road at the position of the vehicle 71 shown in the figure is estimated. In this case,
If you divide the map information into a grid as shown in the figure and store the elevation data of each grid point (indicated by a black circle),
Using the elevation data (a, b, c, d) of the four grids of the section in which 71 exists, each average gradient in the X-axis direction and Y-axis direction of the section is

[0087]

The average gradient in the X-axis direction = (d−b + ca) / 2L The average gradient in the Y-axis direction = (ab−cd) / 2L where L is given by the following formula: Assuming that the vehicle 71 is traveling in the direction of the angle 反 counterclockwise with respect to the X axis direction,

[0088]

[Equation 6] tanΘ = ｛(d-b + ca) / 2L｝ × cosξ + ｛(a-b + c-
d) The road gradient の at the position where the vehicle 71 exists can be obtained by the formula of / 2L｝ × sinξ.

Note that the weight gradient resistance RF is calculated from the road gradient Θ.
To determine ORCE, refer to JP-A-8-219242.

[0090]

[Mathematical formula-see original document] RFORCE = m * g * sin * where m: vehicle weight g: gravitational acceleration may be used.

Here, the case of map information in which altitude data is stored in a grid pattern has been described. However, the present invention is not limited to this. Altitude data is stored at points on the road, Is stored in a point on the road, the road gradient can be estimated.

As described above, in the fifth embodiment, the road gradient at the position where the vehicle is located is estimated based on the map information and the absolute position information from satellites and the like, so that tire puncture and aging deterioration are performed. Thus, the road gradient can be accurately detected without being affected by changes in the driving force characteristics due to changes in the vehicle state.

Further, since it is possible to estimate not only the existing road but also the gradient of the traveling road which is going to go ahead, it is possible to correct the driving force by reading the gradient in advance, so that the driver can respond even more. Good driving force correction is possible. Usually, even if an attempt is made to estimate the road gradient from the output, the driving force and the vehicle acceleration, the actual gradient does not completely match (that is, a deviation occurs) due to a delay in calculation or a delay in the transmission of the driving force of the vehicle. By reading ahead, this deviation can be avoided.

FIG. 10 shows a sixth embodiment, in which the weight gradient resistance is estimated by calculating the rotational force of the drive shaft and adding the reference running resistance and acceleration resistance on a flat road to this. Things.

First, the drive shaft torque calculating means 81 mainly comprises an engine output shaft torque calculating means 82, a torque converter torque amplification ratio calculating means 83, and a drive system loss torque estimating means 84. The engine output shaft torque calculating means 82 calculates the fuel injection amount Tp of the engine and the engine speed EN.
The output shaft torque Te of the engine is obtained by searching a predetermined map from GREV. In the torque amplification ratio calculating means 83 of the torque converter, the ratio between the engine speed ENGREV and the input shaft speed INPREV (output shaft speed of the torque converter) of the transmission is calculated as the speed ratio SLPRTO, and a predetermined map is calculated from this value. By searching,
The torque amplification ratio TAURTO of the torque converter is required.
The drive system loss torque estimating means 84 obtains the loss torque LOSSTRQ by searching a predetermined map from the working oil pressure TGTPRS that has the largest influence on the drive system loss torque.

In the multiplying means 85, the output shaft torque of the engine
Te is multiplied by the torque amplification ratio TAURTO of the torque converter to obtain a primary shaft output torque Tin (= Te × TAURTO).

[0097]

[Equation 8] Tsec = Tin × RATIO−LOSSTRQ Here, the output shaft torque (= drive shaft rotational force) Tsec of the drive shaft is calculated by the equation of RATIO: input / output rotation speed ratio of the transmission.

On the other hand, the reference running resistance calculating means 91 searches a predetermined map from the vehicle speed VSP to obtain a reference running resistance (a running resistance that is a reference on a flat road) RLDT.
RQ is required.

The acceleration detecting means 92 obtains the vehicle acceleration GDATA from the difference between the vehicle speed VSP and the acceleration resistance estimating means 9
In 3, the estimated acceleration resistance AccTRQ on the output shaft is obtained by multiplying the vehicle acceleration GDATA by the equivalent weight Iv of the vehicle viewed from the output shaft.

The output shaft torque Tsec of the drive shaft, the reference running resistance RLDTRQ, and the estimated acceleration resistance determined in this manner.
Using AccTRQ, in the weight gradient resistance estimation means 94,

[0101]

## EQU9 ## The weight gradient resistance RFORCE is calculated by the equation RFORCE = Tsec-RLDTRQ-AccTRQ.

In FIG. 10, the vehicle acceleration is estimated from the vehicle speed. However, the vehicle acceleration may be directly detected by an acceleration sensor.

As described above, in the sixth embodiment, there is no need to provide a new sensor for detecting the weight gradient resistance, so that the weight gradient resistance can be estimated at very low cost.

FIG. 11 shows a target driving force change amount setting means 121 according to the seventh embodiment, which is shown in FIGS. 2 (first embodiment) and FIG. 5 (third embodiment).
This is replaced with the target driving force change amount setting means 21 of the embodiment).

In FIG. 11, the change in the target driving force shown on the horizontal axis (the value obtained by subtracting the final target driving force before a predetermined time from the current target driving force) is positive and the change amount is large. Then, the amount of change in the target driving force per unit time is gradually changed.

As a result, when the road surface is steeper from a flat road to a graded road, a change in driving force is suppressed when the road surface gradient is steep as compared with a case where the road surface gradient is gentle. Fewer shocks.

In FIG. 11, when the change in the target driving force is negative, the change per unit time is made substantially proportional to the change in the target driving force even in a region where the change is large.
The case where the change in the target driving force is negative and the amount of change is large is a case where the change in the road surface gradient is abrupt when the ascending gradient becomes gentle, and in such a case, the driving force sharply decreases. Since the driver becomes insensitive to the torque step at the time, in principle, the target driving force switching speed is given in proportion to the change in the target driving force (change in the road surface gradient when the ascending gradient becomes gentle). It is like that.

FIG. 12 shows the interpolation coefficient change amount setting means 131 of the eighth embodiment, which is replaced by the interpolation coefficient change amount setting means 61 of FIG. 7 (fourth embodiment).

In FIG. 12, when the change (β0−β ₋₁ ) of the interpolation coefficient shown on the horizontal axis is near zero, the amount of change in the interpolation coefficient per unit time is set to zero.

This is to cope with a case where the estimated gradient fluctuates minutely due to noise or the like when traveling on a flat road. For example, when the estimated gradient changes minutely due to noise or the like, the weight gradient resistance calculated based on the estimated gradient changes minutely, and the interpolation coefficient β0 obtained from the weight gradient resistance changes minutely. Therefore, if the amount of change Δβ per unit time is determined in response to such a small change in the interpolation coefficient β0, a small change in the driving force occurs even when the vehicle is traveling on a flat road.

On the other hand, according to the characteristics shown in FIG. 12, even when the interpolation coefficient β0 fluctuates slightly due to the influence of the estimated gradient such as noise, the final interpolation coefficient β does not fluctuate. In addition, it is possible to suppress a small change in driving force that does not conform to the intention when traveling on a flat road.

FIG. 13 shows a target driving force realizing means 151 according to the ninth embodiment.

The target driving force realizing means 151 comprises a transmission input / output ratio control means 152, a transmission input / output ratio realizing means 153, a target engine output torque calculating means 154, and an engine output torque realizing means 155.

First, the target driving force tTd corresponding to the gradient and the vehicle speed V
The transmission input / output ratio control means 152, to which the SP is input, obtains a target input / output rotational speed ratio tRATIO by searching a predetermined map from these values. here,
Although a map for obtaining the target input / output rotation speed ratio tRATIO is used for both parameters, the present invention is not limited to this. For example, in the input / output ratio control of a transmission, a target value of the input shaft speed is usually obtained in many cases. Therefore, the target input / output speed ratio tRATIO May be required.

The target input / output rotational speed ratio tR thus obtained
ATIO is realized by the transmission input / output ratio realizing means 153.

The target engine output torque calculating means 154 calculates the target engine output torque tTe by dividing the target driving force tTd corresponding to the gradient by the input / output speed ratio RATIO realized by the transmission 103. Then, in the engine output torque realizing means 155 composed of the engine torque control means 156 and the engine 101, the throttle operation amount, the fuel injection amount, the ignition timing and the like are controlled by the engine torque control means 156 in order to realize the target engine torque tTe. Then, a command (command value such as a throttle operation amount, a fuel injection amount, an ignition timing, etc.) from the engine torque control means 66 is sent to the engine 101.

As described above, in the ninth embodiment, in order to realize the target driving force corresponding to the gradient, the target input / output speed of the transmission having a slow response is determined in determining the target input / output rotational speed ratio and the target engine output torque. Since the rotational speed ratio is determined first, the target driving force corresponding to the gradient can be realized with good responsiveness.

In the embodiment shown in FIG. 11, the case of the target driving force has been described, but the same can be applied to the interpolation coefficient. For example, in the characteristics of FIG. 11, the target driving force may be replaced with an interpolation coefficient. Similarly,
In the embodiment shown in FIG. 12, the case of the interpolation coefficient has been described, but the same can be applied to the target driving force. For example, in the characteristic of FIG. 12, the interpolation coefficient may be replaced with the target driving force.

[Brief description of the drawings]

FIG. 1 is a control system diagram of an entire vehicle according to the present invention.

FIG. 2 is a block diagram showing processing performed by a PCM 50.

FIG. 3 is a flowchart corresponding to the block diagram of FIG. 2;

FIG. 4 is a block diagram of a second embodiment.

FIG. 5 is a block diagram illustrating processing performed by a PCM 50 according to a third embodiment.

FIG. 6 is a flowchart corresponding to the block diagram of FIG. 5;

FIG. 7 is a block diagram illustrating processing performed by a PCM 50 according to a fourth embodiment.

FIG. 8 is a flowchart corresponding to the block diagram of FIG. 7;

FIG. 9 is a road map for explaining a calculation of a road gradient according to the fifth embodiment.

FIG. 10 is a block diagram of a sixth embodiment.

FIG. 11 is a block diagram of a seventh embodiment.

FIG. 12 is a block diagram of an eighth embodiment.

FIG. 13 is a block diagram of a ninth embodiment.

FIG. 14 is a diagram corresponding to claims of the first invention.

FIG. 15 is a diagram corresponding to a claim of the eighth invention.

[Explanation of symbols]

 12 Normal target driving force calculation means 15 Slope corresponding target driving force calculation means 20 Target driving force change speed adjusting means 21 Target driving force change amount setting means 41 Slope corresponding target driving force calculation means 44 Target driving force interpolation calculation means 50 PCM 60 interpolation Coefficient change speed adjusting means 61 Interpolation coefficient change amount setting means

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) // F16H 59:18 59:44 59:66 (72) Inventor Masaaki Uchida 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor (72) Inventor Hiroro Nishijima 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture F-term (reference) 3D041 AA32 AB01 AC01 AC15 AC19 AC26 AD04 AD10 AD31 AD41 AD47 AD51 AE04 AE07 AE09 AE31 AE41 AE45 AF01 AF09 3G065 CA21 DA04 EA04 FA09 FA12 GA11 GA29 GA31 GA41 GA46 GA49 GA50 KA33 3G093 AA05 AA06 BA15 CB00 CB06 DA06 DB00 DB05 DB11 DB15 DB18 DB21 EA05 EA09 EA13 EB03 EB04 EC02 FA07 FA10 FB03 3G301 HA01 NC03 NC03 NC03 PF01Z PF02A PF02Z PF05Z PF07Z PG00Z 3J052 AA04 FA01 FA06 FB31 GC13 GC23 GC46 GD05 GD11 HA02 HA11 HA12 LA01

Claims (12)

[Claims] 1. A means for detecting an accelerator operation amount; a means for detecting a vehicle speed; Means for calculating; means for detecting the weight gradient resistance; means for calculating a target driving force of the vehicle according to the detected weight gradient resistance and the normal target driving force as a target driving force corresponding to the gradient; Means for adjusting the rate of change of the gradient corresponding target driving force according to the change in the gradient corresponding target driving force, calculating the adjusted gradient corresponding target driving force as the final target driving force, and realizing the final target driving force. Means for controlling vehicle driving force. 2. The method according to claim 1, wherein the changing speed of the target driving force corresponding to the gradient is changed to a side where the target driving force corresponding to the gradient is increased and the final target driving force is changed with respect to the changing amount in an area where the change amount is large. The vehicle driving force control device according to claim 1, wherein a ratio of the speed is reduced. 3. The method of claim 2, wherein the changing speed of the target driving force corresponding to the gradient is adjusted to zero when the change of the target driving force corresponding to the gradient is within a predetermined range near zero. The vehicle driving force control device according to claim 1, wherein: 4. The target driving force calculating means corresponding to the gradient is configured to calculate a driving force correction amount of a percentage less than the weight gradient resistance as 100%, and to calculate the calculated driving force correction amount to the normal target. 4. The vehicle driving force control device according to claim 1, further comprising means for setting a value added to the driving force as a target driving force corresponding to the gradient. 5. The vehicle driving force control device according to claim 4, wherein the driving force correction amount is 30% to 70% of the magnitude of the weight gradient resistance. 6. The vehicle driving force control device according to claim 4, wherein the ratio of the driving force correction amount to the weight gradient resistance is a value that decreases as the weight gradient resistance increases. 7. The target driving force calculating means corresponding to the gradient corresponds to a value obtained by adding a value of a predetermined less than 100% to the normal target driving force assuming that a predetermined weight gradient resistance which is not a flat road is 100%. Means for preliminarily setting the gradient-corresponding reference target driving force, means for calculating an interpolation coefficient from the detected weight gradient resistance and the predetermined weight gradient resistance, and 4. A vehicle driving force control apparatus according to claim 1, further comprising means for calculating a value obtained by interpolating the force and the normal target driving force as a target driving force corresponding to a gradient. . 8. A means for detecting an accelerator operation amount, a means for detecting a vehicle speed, and a target driving force for a vehicle on a flat road corresponding to the detected accelerator operation amount and vehicle speed. And a target driving force corresponding to a value obtained by adding a predetermined value of less than 100% to the normal target driving force as a gradient target reference target driving force. Means for detecting a weight gradient resistance; means for calculating an interpolation coefficient from the detected weight gradient resistance and the predetermined weight gradient resistance; and an interpolation coefficient according to a change in the calculated interpolation coefficient. Means for adjusting the change speed of the gradient, and calculating the adjusted interpolation coefficient as a final interpolation coefficient; and using the final interpolation coefficient, the gradient corresponding reference target driving force and the normal target driving force. A means for calculating a value obtained by interpolating the above as the final target driving force, and means for realizing the final target driving force. 9. The adjustment of the change speed of the interpolation coefficient is performed by reducing the ratio of the change speed of the final interpolation coefficient to the change amount in a region where the interpolation coefficient increases and the change amount is large. The vehicle driving force control device according to claim 8, wherein 10. The method according to claim 1, wherein the change rate of the interpolation coefficient is adjusted when the change of the interpolation coefficient is within a predetermined range near zero.
9. The vehicle driving force control device according to claim 8, wherein the change speed of the final interpolation coefficient is set to zero. 11. A means for detecting the weight gradient resistance, comprising: means for detecting an absolute position of the vehicle; The vehicle driving force control apparatus according to any one of claims 1 to 10, further comprising means for calculating a weight gradient resistance from the estimated road gradient. 12. The means for detecting the weight gradient resistance includes: means for calculating a driving shaft rotational force; means for calculating a reference running resistance on a flat road according to the vehicle speed as a reference running resistance; Means for detecting the acceleration of the vehicle, means for estimating the acceleration resistance of the vehicle based on the detected acceleration, and a value obtained by subtracting the reference running resistance and the acceleration resistance from the calculated drive shaft rotational force. The vehicle driving force control device according to any one of claims 1 to 10, further comprising means for estimating the weight gradient resistance.