JPH04365935A - Driving force control device for vehicle - Google Patents

Abstract

PURPOSE:To decrease pedal operating frequency at the time of traffic jam, when shifting position of an automatic transmission is in a running range, by increasing a driving torque to be supplied to a driving wheel under a condition that congestion of load is small, compared to the time that the congestion is large. CONSTITUTION:A throttle valve 3 arranged on an intake system 2 of an engine 1 is opened or closed by means of a servomotor 4. An output of the engine 1 is transmitted to a driving wheel, not shown, through a torque converter 5 or a multistage automatic transmission 6. The servomotor 4 or the like is controlled by each controlling unit 10 based on outputs of sensors or switches 11 to 16 which detect an operation condition of a vehicle. The controlling unit 10, that is, carries out controlling in such a manner that a driving torque applied to the driving wheel is increased when a shifting position of the automatic transmission 6 is in a running range and under a condition that congestion of load is small, compared to the time that the congestion is large. Pedal operating frequency at the time of traffic jam is decreased, accordingly.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving force control system for a vehicle.

0002

[Prior Art] In a vehicle equipped with an automatic transmission, as long as the shift position of the automatic transmission is in the driving range, the engine and drive wheels are connected, so the accelerator pedal is not pressed. Even if released, a so-called creep phenomenon occurs in which the vehicle moves slowly.

Japanese Unexamined Patent Publication No. 61-282652 discloses a technique in which a clutch is provided in the power transmission path between the engine and the driving wheels, and creep is suppressed by disengaging the clutch. Therefore, if this technology is developed, it will be possible to change the creep speed by adjusting the degree of slippage of the clutch.

[0004] Vehicles with automatic transmissions have the advantage of reducing the driver's pedal operations; however, when driving on congested roads, vehicles with automatic transmissions still have to step on the brake pedal and accelerator pedal in order to follow the vehicle in front. It is necessary to change it frequently.

[0005]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a vehicle with an automatic transmission that reduces the frequency of pedal changes required when driving in traffic congestion, thereby reducing driver fatigue. An object of the present invention is to provide a driving force control device.

[0006]

[Means for Solving the Problems] The present invention has been made by focusing on the fact that the way a vehicle runs differs depending on the degree of congestion of the road, that is, the degree of congestion. In other words, when the degree of traffic congestion is high, that is, when the road is extremely crowded, you have to drive slowly while clinging to the vehicle in front, whereas when the degree of traffic congestion is low, that is, when the road is relatively congested, you have to drive slowly. , you have to drive relatively quickly in order to follow the vehicle in front while observing its movements.

In consideration of these points, the present invention provides a shift position detection means for detecting whether the shift position of the automatic transmission is in the forward range, and a shift position detection means for detecting whether or not the shift position of the automatic transmission is in the forward range. traffic jam detection means for detecting a traffic jam; drive torque adjustment means for adjusting the drive torque applied to the drive wheels when the accelerator is released; and signals from the shift position detection means and the traffic jam detection means to determine the shift position of the automatic transmission. drive torque control means for increasing the drive torque applied to the drive wheels when the degree of congestion is small compared to when the degree of congestion is large, depending on the degree of congestion on the road on which the vehicle is traveling when the vehicle is in the forward range; The configuration includes the following.

[0008] As a traffic jam detection means, Japanese Patent Laid-Open No. 59
As disclosed in Japanese Patent Publication No. 200846, it is already known to detect the degree of congestion based on the average vehicle speed and the rate of change of the instantaneous vehicle speed with respect to the average vehicle speed.

[0009]

[Operation] According to the present invention, when the degree of traffic congestion is small,
The driving force when the accelerator is released is automatically increased, thus achieving a higher vehicle speed. On the other hand, when the degree of traffic congestion is high, the driving force when the accelerator is released is automatically reduced, allowing so-called slow driving.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, reference numeral 1 denotes an engine. A throttle valve 3 disposed in an intake system 2 of the engine 1 is linked to a servo motor 4, and the throttle valve 3 is opened and closed by the driving force of the motor 4. The output is transmitted to drive wheels (not shown) via a multi-stage automatic transmission 6 equipped with a torque converter 5 and a hydraulic control circuit (not shown).

In the figure, reference numeral 10 is a control unit for engine control and automatic transmission control;
is composed of, for example, a microcomputer, and includes a CPU, ROM, and RAM, as is known.

Signals from sensors or switches 11 to 16 are input to the control unit 10, and the control unit 10 sends control signals to the servo motor 4 and the plurality of solenoid valves 17. is now output. The sensor 11 detects the opening degree of the throttle valve 3. The sensor 12 detects the engine rotation speed. The sensor 13 detects the amount of depression of the accelerator pedal 20, that is, the opening degree of the accelerator. The sensor 14 is, for example, a transmitting and receiving ultrasonic sensor 1 embedded in a front bumper.
4a to detect the distance between the vehicle and the vehicle in front. The switch 15 is a manual switch that switches the speed change control characteristics of the automatic transmission 6 between a power mode that emphasizes output and an economy mode that emphasizes fuel efficiency. Incidentally, since changing the speed change control characteristics (mode switching) of the automatic transmission 6 has been well known in the past, a description thereof will be omitted. The sensor 16 detects a set gear (set gear position) (whether the vehicle is in the forward range or not, and the vehicle speed is determined in cooperation with the engine speed). As is known, the plurality of solenoid valves 17 are configured to realize a desired gear stage by a combination of ON and OFF states.

Next, the control contents of the control unit 10 will be schematically explained. In this control unit 10,
Under the condition that the vehicle is in the forward range, the degree of traffic congestion is first detected, and based on the degree of traffic congestion, when the degree of traffic congestion is small, the driving force is automatically increased when the accelerator is released.
While the system allows a high vehicle speed to be obtained, when the degree of traffic congestion is high, the driving force when the accelerator is released is automatically reduced to enable so-called leisurely driving. The degree of traffic congestion is determined by focusing on the following distance, the time in a certain driving section from starting to stopping (interval time), the maximum vehicle speed within that certain driving section, etc., and the longer the following distance and the interval time, the more In addition, the higher the maximum vehicle speed, the smaller it is judged to be, and the smaller the degree of congestion, the larger the throttle opening y when the accelerator is released to adjust the driving force when the accelerator is released. There is. More specifically, in this embodiment, fuzzy control is used as a method of obtaining the throttle opening degree y according to the degree of traffic congestion, and the membership function of this fuzzy control is the inter-vehicle distance D and the inter-vehicle distance D. The valve time T and the maximum vehicle speed V are used, and the throttle opening y is determined according to FIGS. 2 to 5 under the following fuzzy rules (a) to (h). In addition, F, M, E, P, N, MF, MN, NE, NP, in the following fuzzy rules,
L, S, etc. indicate characteristic lines in FIGS. 2 to 5. (a) IF Inter-vehicle distance D is F (long distance)
{Antecedent}, then M (mode) is
E (economy) {Consequent} (b) IF Inter-vehicle distance D is MF (medium-long distance) {Antecedent}, then M (mode) is
P (power) {Consequent part} (c) IF Inter-vehicle distance D is MN (medium-short distance) {Antecedent part}, then M (mode) is
NP (medium power) {Consequent part} (d) IF Inter-vehicle distance D is N (short distance)
{Antecedent}, then M (mode) is
E (economy) {consequent} (e) IF maximum vehicle speed V is H (high vehicle speed),
T (interval time) is L (long time) {antecedent}, then M (mode) is P (power
) {Consequent} (f) IF Maximum vehicle speed V is
L (low vehicle speed), T (interval time) isL (
long time) {antecedent}, then M (mode) i
s E (economy) {consequent} (g) IF maximum vehicle speed V is H (high vehicle speed),
T (interval time) isS (short time) {antecedent}, then M (mode) is NE (medium economy) {consequent} (h) IF Maximum vehicle speed V is L (low vehicle speed) ,
T (interval time) isS (short time) {antecedent part}, then M (mode) is E (economy) {consequent part} In other words, in the antecedent part, as shown in Figure 2, , membership function values D1, D2 are determined from the inter-vehicle distance D, membership function values V1, V2 are determined from the maximum vehicle speed V as shown in FIG. 3, and further, as shown in FIG. From time T to membership function value T
1 and T2 are obtained, and using these values, w1 to w4 are obtained from Equations 1 to 4 below.

[Math 1]

[Math 2]

[Math 3]

[Equation 4] In the consequent part, as shown in FIG.
2 to find M1 and M2, and the above w1 to w
4, find modes m1 to m4. Then, using these values, the throttle opening y is calculated from the following equation 5 in the range of about 0 to 2% based on the center of gravity method, and it is calculated as shown in Fig. 6.
As shown in , it is used as the throttle opening when the accelerator is released. In addition, according to these conditions, D≦5
When m, V≦10Km/h, T≦5 seconds, it is judged as a traffic jam (100% congestion level), D≧20m, V≧40Km/h
, when T≧20 seconds, it is determined that the vehicle is running normally (congestion degree 0%).

[Math 5]

Next, in order to make the above-mentioned control content clearer, it will be explained with reference to the flowcharts of FIGS. 7 and 8. Note that S indicates a step. First, the accelerator opening α, vehicle speed VSP, and inter-vehicle distance Dis are read (S1 to S3),
It is determined whether the flag DLS is "0" (S4). This flag DLS indicates whether or not the vehicle is in the traffic jam determination mode. When the flag DLS is "1", the vehicle is in the traffic jam determination mode, and when the flag DLS is "0", it is determined that the vehicle is not in the traffic jam determination mode.

When S4 is YES, as shown in FIG. 8, after resetting the timer and setting the read inter-vehicle distance Dis to inter-vehicle distance D (S32, S33), it is determined whether the vehicle speed VSP exceeds 5 Km/h. (S34)
. This "5 Km/h" is a criterion for determining whether or not the traffic jam determination mode is entered. When this S34 is NO, it is assumed that the mode is not in the traffic congestion determination mode, and the process directly proceeds to S23. On the other hand, when S34 is YES, it is assumed that the traffic congestion determination mode has been entered, and the flag DLF is set to "1" (S35), and then the process proceeds to S23. I will move on.

On the other hand, as shown in FIG.
When the vehicle is in the traffic jam detection mode, it is first determined whether the vehicle speed VSP exceeds 40 km/h ( S5). If S5 is YES, the above state exists, and the process proceeds to S17. However, if the throttle gain suddenly changes when the accelerator is pressed during the process, it will give the driver a sense of discomfort, so to prevent this, the accelerator must be released. The throttle control gain is changed under the condition (S6, S7).

When S5 is NO, it is considered that there is a traffic jam, so at this time, VSP(n-
2) The vehicle speeds read in VSP(n-1) and VSP(n) are sequentially increased to VSP(n-3) and VSP(
n-2) and is read into VSP (n-1) (S8), and then the processes of S9 to S12 are performed. As a result, the local maximum value of the vehicle speed (maximum vehicle speed Vmax) closest to the current time is determined. To find such maximum vehicle speed Vmax,
This is because the maximum vehicle speed Vmax significantly reflects traffic congestion. Note that Vmax in S11 cannot be less than the initial value V0 because the initial value V0 is set to Vmax in S21, which will be described later.

Next, a timer is counted up to count the time t from start to stop (S13).
It is determined whether the time t exceeds 20 seconds (S1
4). This "20 seconds" is a criterion for determining whether or not the vehicle has escaped the traffic jam. If this t does not exceed 20 seconds, proceed to S17 to continue counting that t, while if t exceeds 20 seconds, taking into account the intention to stop it, t is 2 on the condition that the accelerator is released.
It is set to 0 seconds (S15, S16).

Next, it is determined whether the inter-vehicle distance Dis exceeds 20 meters (S17). This "20m" is also a criterion for determining whether or not the vehicle has escaped the traffic jam. If the inter-vehicle distance Dis exceeds 20 m, there is no need to use a longer inter-vehicle distance Dis as a criterion, so the inter-vehicle distance D is set to 20 m (S18
), if Dis does not exceed 20 m, the inter-vehicle distance Di at Vmax in S12 is used as a criterion for determining the degree of congestion.
s is held and set as the inter-vehicle distance D (S19). The reason why the inter-vehicle distance at Vmax is determined is that the aforementioned maximum vehicle speed Vmax reflects traffic congestion, and it also reflects traffic congestion.

Next, it is determined whether the vehicle speed VSP is less than 3 km/h (S20). This "3 Km/h" is a criterion for determining whether the vehicle has stopped, that is, whether the vehicle has stopped in the traffic jam determination mode. When this S20 is NO, the time t of the timer up to that point is set as the interval time T, and the maximum vehicle speed Vmax is set as the maximum vehicle speed V, while Vmax is set to the initial value V0 in preparation for the start of the next traffic jam determination mode.
is set (S21), and then the flag DLF is reset (S22).

Next, under fuzzy control, as described above,
D1 based on D such as S19 (or S18, S33)
, D2 (S23, see FIG. 2), and T1, T2 based on T in S21 (S24, see FIG. 4),
Furthermore, V1 and V2 are determined based on V in S21 (S25, see FIG. 3). Then, T1 and T2 of S24
Then, w1 to w4 are calculated from V1 and V2 in S25 (S26), and modes m1 to m4 are determined based on D1 and D2 in S23 (S27, S28 (Fig.
reference)). After that, the above values are substituted into Equation 5 to calculate the throttle opening y (S29), and a control signal is output to the servo motor 4 in order to realize this throttle opening y for the throttle valve 3. (S30, S31). As a result, the throttle opening degree y when the accelerator is released is adjusted according to the degree of traffic congestion, as shown in FIG.
This means that the frequency of pedal changes required when driving in traffic jams can be reduced.

[0022]

As described above, the present invention provides driving force control for a vehicle equipped with an automatic transmission that reduces driver fatigue by reducing the frequency of pedal depressing required when driving in traffic jams. equipment can be provided.

[Brief explanation of drawings]

FIG. 1 is an overall system diagram showing one embodiment of the present invention.

FIG. 2 is a diagram illustrating processing of inter-vehicle distance D in the antecedent part of fuzzy control.

FIG. 3 is a diagram illustrating processing of the maximum vehicle speed V in the antecedent part of fuzzy control.

FIG. 4 is a diagram illustrating processing of interval time T in the antecedent part of fuzzy control.

FIG. 5 is a diagram illustrating processing in the consequent part of fuzzy control.

FIG. 6 is a diagram illustrating throttle opening adjustment when the accelerator is released.

FIG. 7 is a flowchart showing a control example of the present invention.

FIG. 8 is a flowchart showing a continuation of FIG. 7;

[Explanation of symbols]

4 Servo motor 6 Automatic transmission 10 Control unit 12 Sensor 13 Sensor 14 Sensor 15 Switch 16 Sensor

Claims (6)

[Claims] 1. Shift position detection means for detecting whether the shift position of the automatic transmission is in the forward range; congestion detection means for detecting the degree of congestion on the road on which the vehicle is traveling; drive torque adjusting means for adjusting the applied drive torque; receiving signals from the shift position detecting means and the traffic jam detecting means;
When the shift position of the automatic transmission is in the forward range, depending on the degree of traffic congestion on the road on which the vehicle is traveling, the driving torque applied to the drive wheels is increased when the degree of traffic congestion is small compared to when the degree of traffic congestion is large. A driving force control device for a vehicle, comprising: a driving torque control means for controlling the driving torque. 2. The automatic transmission according to claim 1, wherein the automatic transmission includes a torque converter, the drive torque adjustment means adjusts the creep speed of the vehicle, and the drive torque control means is configured to adjust the creep speed of the vehicle when the degree of congestion is small. The higher the creep rate, the higher the creep rate. 3. The vehicle according to claim 1, wherein the congestion detection means detects the degree of congestion based on the distance between vehicles. 4. The vehicle according to claim 1, wherein the traffic congestion detection means detects the degree of traffic congestion based on an interval time from when a vehicle starts until it stops. 5. The vehicle according to claim 1, wherein the traffic congestion detection means detects the degree of traffic congestion based on the maximum vehicle speed from when the vehicle starts until it stops. 6. In claim 2, the drive torque adjusting means includes an actuator that adjusts the throttle opening degree when the accelerator is released, and the drive torque control means adjusts the throttle opening degree when the accelerator is released as the degree of congestion is smaller. Something that increases the throttle opening.