JP3154219B2 - Vehicle control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle control device,
More specifically, the present invention relates to a technique for controlling a vehicle based on a detection result of a gradient resistance.

[0002]

2. Description of the Related Art An automatic transmission for a vehicle is provided with a shift map in which gear positions are set in advance in accordance with an accelerator opening and a vehicle speed, and determines a gear position with reference to the shift map. General. However, the shift pattern is set on the assumption of a general flat road running state, and for example, when climbing up or downhill, an appropriate shift characteristic (speed ratio) may not be obtained.

[0003] Therefore, the gradient (gradient resistance) of the road surface on which the vehicle is traveling is obtained based on the driving force, air resistance, rolling resistance, and acceleration resistance, and the shift pattern is changed based on the gradient resistance. There have been proposed various automatic shift controls for obtaining an appropriate shift characteristic at the time of climbing or descending a hill (see Japanese Patent Publication No. 59-8698).

[0004]

However, when the brake is operated to determine the gradient resistance of the vehicle, the engine output torque apparently decreases in accordance with the braking force of the brake. However, it is impossible to accurately detect the index indicating the running resistance, whereby the gradient resistance is erroneously detected, and there is a possibility that the shift characteristic cannot be appropriately controlled.

As a technique for solving such a problem, Japanese Unexamined Patent Application Publication No.
Japanese Patent Application Laid-Open No. 71625/1995 discloses a method of stopping uphill control of a transmission based on a gradient detection result during braking operation. Further, Japanese Patent Application Laid-Open No. 61-79056 discloses a technique of calculating the running gradient or the like immediately after the start of running of the vehicle, thereby avoiding the calculation of the running resistance during the brake operation. Further, JP-A-2-29667
Japanese Patent Application Laid-Open Publication No. H11-163873 discloses that when a gearshift control suitable for traveling on an uphill road is executed, if a brake operation is performed, the speed ratio up to that time is maintained while the brake operation is being performed, and the brake operation is performed according to the brake operation. In this way, it is possible to avoid erroneously detecting the running resistance and thereby performing inappropriate shift control.

[0006] Incidentally, none of the above-mentioned countermeasure techniques execute shift control based on new detection of gradient resistance during a brake operation. For this reason, for example, when running on a long downhill, if the state where the brakes are lightly applied continues for a long time, even if the road surface condition (road surface gradient) changes during such a relatively long brake operation period. However, there is a possibility that the shift control corresponding to such a change in the road surface condition is not performed at all, and the intended effect of making the shift characteristics at the time of ascending or descending a slope appropriate based on the slope resistance cannot be exhibited at all. there were.

That is, in the conventional control, if the brake is operated, it is considered that an error occurs in the detection of the gradient resistance due to the generation of the braking force, and even if the braking force is small, it greatly affects the detection of the gradient resistance. Even in such a situation, the shift control corresponding to the change in the gradient resistance is not performed at all. The present invention has been made in view of the above problems, and has as its object to provide an opportunity to detect a gradient during a brake operation while avoiding erroneous detection of a gradient resistance due to a brake operation. I do.

[0008]

A vehicle control apparatus according to the first aspect of the present invention is configured as shown in FIG. In FIG. 1, the gradient resistance calculating means calculates the gradient resistance of the vehicle based on the driving force, acceleration resistance, rolling resistance, and air resistance, and the control means controls the vehicle based on the gradient resistance calculated by the gradient resistance calculating means. Is controlled. On the other hand, the braking force estimation means determines that the predetermined time
The braking force of the vehicle is estimated based on the driving force, the acceleration resistance, the rolling resistance, the air resistance at the time when the elapsed time has elapsed, and the gradient resistance calculated by the gradient resistance calculating means immediately before the brake operation. The control suspending means suspends the control based on the gradient resistance by the control means when the braking force estimated by the braking force estimating means exceeds a predetermined value.

[0009]

[0010]

[0011]

[0012]

According to the control apparatus for a vehicle according to the first aspect of the present invention, a predetermined control target (for example, a shift pattern or a lock pattern) of the vehicle is determined based on a gradient resistance calculated according to a driving force, an acceleration resistance, a rolling resistance, and an air resistance. Control of the up-clutch, etc.), but a predetermined time has elapsed since the start of the brake operation.
When the braking force of the vehicle estimated based on the driving force, acceleration resistance, rolling resistance, air resistance at the time when the vehicle is driven, and the gradient resistance calculated immediately before the braking operation exceeds a predetermined value,
The control based on the gradient resistance is stopped.

[0013]

[0014]

[0015]

[0016]

Embodiments of the present invention will be described below. In FIG. 2 schematically showing a system configuration of an embodiment, an automatic transmission 2 is provided on an output side of an internal combustion engine 1 mounted on a vehicle (not shown). The automatic transmission 2 includes a hydraulic torque converter 3 interposed on the output side of the engine 1 and a gear type transmission 4 connected via the hydraulic torque converter 3.
And a hydraulic actuator 5 for performing an operation of connecting and releasing various transmission elements in the gear transmission 4. The operating oil pressure for the hydraulic actuator 5 is controlled through various electromagnetic valves, but here only the shift electromagnetic valves 6A and 6B for automatic shifting are shown. Reference numeral 7 denotes an output shaft of the automatic transmission 2.

Here, an oil pump 8 driven by an input shaft of the gear type transmission 4 is used to obtain a line pressure which is an operating oil pressure for the hydraulic torque converter 3 and the hydraulic actuator 5, and a pilot valve 9. , Solenoid valve 10, pressure modifier valve 11
And a pressure regulator valve 12.

The pilot valve 9 regulates the discharge pressure of the oil pump 8 to a pilot pressure acting on the electromagnetic valve 10. The electromagnetic valve 10 is duty-controlled as described below,
The pilot pressure is adjusted to a throttle pressure according to the operating conditions. The pressure modifier valve 11 adjusts the pilot pressure to a pressure modifier pressure according to the throttle pressure, and acts on the pressure regulator valve 12. In the pressure regulator valve 12, the oil pump discharge pressure is adjusted to a line pressure proportional to the pressure modifier pressure, and sent to a hydraulic circuit such as the hydraulic torque converter 3 and the hydraulic actuator 5.

The control unit 13 receives signals from various sensors. As the various sensors, a potentiometer type throttle sensor 15 for detecting the opening TVO of the throttle valve 14 of the intake system of the engine 1 is provided. Further, a crank angle sensor 16 is provided on a crank shaft of the engine 1 or a shaft (cam shaft) that rotates in synchronization with the crank shaft. The signal from the crank angle sensor 16 is
For example, a pulse signal for each reference crank angle is used to calculate the engine speed Ne based on the cycle.

The intake system of the engine 1 is provided with a hot-wire type air flow meter 17 for detecting an intake air flow rate Q. From the intake air flow rate Q detected by the air flow meter 17 and the engine rotation speed Ne calculated based on the signal of the crank angle sensor 16, the basic fuel used as the basis for calculating the fuel injection amount by the electronically controlled fuel injection device is calculated. Injection amount Tp =
K × Q / Ne (K is a constant) is calculated.

A vehicle speed sensor 18 for detecting a vehicle speed VSP by detecting a rotation speed No of the output shaft 7 of the automatic transmission 2 is provided. Further, a turbine rotation sensor 19 for detecting a turbine rotation speed Nt in the fluid torque converter 3 is provided. Further, a brake switch 20 is provided which detects depression of a brake pedal for operating a brake device (not shown) of the vehicle and is turned ON when the brake pedal is depressed.

The control unit 13 has a built-in unit for engine control (fuel injection and ignition timing control) and a unit for automatic transmission control, so that the units can exchange signals. ing. The unit for automatic shift control mainly performs shift control and line pressure control. The automatic shift control is performed in accordance with the operation position of a select lever (not shown) operated by the driver. In particular, when the select lever is in the D range, the throttle valve opening T
The shift positions of the first to fourth speeds are automatically set in accordance with the VO and the vehicle speed VSP, and the on / off combination of the shift electromagnetic valves 6A and 6B is controlled. Control to shift position.

Here, in the combination of the automatic transmission 2 and the engine 1 as described above, the shift pattern, the engagement force of the lock-up clutch (the predetermined control target of the vehicle), etc.
It is desired to change it according to the running resistance (especially the slope resistance) of the vehicle on which the engine 1 is mounted. Therefore, the control unit 13 calculates the gradient of the road surface (gradient resistance) as shown in the flowcharts of FIGS. 3 and 4, and according to the road surface gradient (gradient resistance), the shift pattern (speed ratio) in the automatic transmission. And the engagement force of the lock-up clutch.

In this embodiment, the gradient resistance calculation procedure
The control unit 13 has functions as a step, a control unit, a braking force estimation unit , and a control suspension unit as shown in the flowcharts of FIGS. In the flowchart of FIG. 3, in step 1 (S1 in the figure, the same applies hereinafter), the driving force F is calculated.

Specifically, a turbine torque Tt is obtained based on the throttle valve opening TVO detected by the throttle sensor 15 and the turbine rotation speed Nt detected by the turbine rotation sensor 19, and the turbine torque Tt and the transmission , The driving force F is calculated as F = Tt × i × if × k using the gear ratio i, the final gear ratio if, and the conversion coefficient k.

In step 2, the acceleration resistance is calculated. The acceleration resistance can be obtained as an acceleration a from the rate of change of the vehicle speed VSP detected by the vehicle speed sensor 18, and as a product ma of the acceleration a and a standard vehicle weight m stored in advance. In step 3, the sum RL of the rolling resistance and the air resistance of the vehicle is set based on the vehicle speed VSP detected by the vehicle speed sensor 18.

In step 4, it is determined whether or not the brake switch 20 was OFF (the brake pedal is not depressed) at the time of the previous execution of this routine. It is determined whether or not the brake switch 20 is currently ON. When it is determined in step 5 that the brake switch 20 is ON, that is, when it is time to start the brake operation, the process proceeds to step 6, where the brake braking force is estimated.

The control for estimating the braking force in step 6 is shown in detail in the flowchart of FIG. In the flowchart of FIG.
Then, the gradient resistance mg · sin θ calculated in the previous execution of the flowchart of FIG. 3 is read. The gradient resistance mg
・ Sin θ (m = vehicle weight, g = gravity acceleration, sin θ = gradient) is given by mg · sin θ = F−
It is obtained as ma-RL. That is, in the present embodiment, the values correlated to the gradient resistance of the vehicle correspond to the driving force F, the acceleration resistance ma, and the rolling / air resistance RL, and the driving parameters of the vehicle as the basis for calculating these values are: The throttle valve opening TVO, the turbine rotation speed Nt, the gear ratio i of the transmission, the vehicle speed VSP, and the like are equivalent.

In step 22, it is determined whether or not a predetermined time has elapsed since the start of the brake operation. When the predetermined time has elapsed, the routine proceeds to step 23. In step 23, the acceleration resistance ma at that time is obtained. In step 24, the driving force F is calculated as described above. In step 25, the vehicle speed VSP at that time is calculated.
To determine the rolling / air resistance RL.

In step 26, the gradient resistance mg · sin θ obtained from the acceleration resistance ma, the driving force F, the rolling / air resistance RL immediately before the start of the brake operation, and the time when a predetermined time has elapsed after the start of the brake operation Acceleration resistance m
The brake braking force FB is obtained as FB = F ′ − (ma ′ + RL ′ + mg · sin θ) based on a ′, the driving force F ′, and the rolling / air resistance RL ′ .

That is, the driving force F and the running resistance (ma + RL +
mg · sin θ) depends on the brake braking force FB.
Driving force F−running resistance (ma + R)
L + mg · sin θ) to estimate the brake braking force FB
Wear. Therefore, just before the start of the brake operation and the brake operation
Gradient resistance mg ・ sin between the time when a predetermined time has elapsed after the start
Assuming that there is no change in θ (road gradient),
Acceleration resistance ma 'at the time when a predetermined time has elapsed after the start, drive
Force F ', rolling / air resistance RL' and opening of brake operation
Acceleration resistance ma, driving force F, rolling / air resistance R just before starting
From the gradient resistance mg · sin θ (road surface gradient) obtained from L
This is for estimating the brake braking force FB.

In the above description, it is assumed that the gradient resistance obtained immediately before the start of the braking operation is constant within a predetermined time from the start of the braking operation. good. This is because a large braking force is not actually generated immediately after the braking operation, and the gradient resistance is not erroneously detected due to the influence of the braking force.

Returning again to the flowchart of FIG. 3, after estimating and calculating the brake braking force FB in step 6, and under other conditions (during the continuation of the brake operation and when the brake is not operated) Proceeding to step 7, assuming that there is no brake braking force FB, the gradient resistance m
g · sin θ (= F−ma−RL) is calculated. In the next step 8, it is determined whether the brake switch 20 is ON or OFF. When the brake switch 20 is OFF and the brake is not operated, the brake braking force does not become an error factor of the gradient resistance. Then, the speed change pattern is changed based on the gradient resistance mg · sin θ (road surface gradient) calculated in step 7 to automatically change the speed to a speed ratio suitable for climbing up and downhill.

On the other hand, when it is determined in step 8 that the brake switch 20 is ON, it is determined whether or not the braking force estimated in step 6 exceeds a predetermined value.
Here, even if the brake switch 20 is ON, in a state where the braking force is equal to or less than the predetermined value and is sufficiently small, the braking force is detected by the gradient resistance mg · sin θ (shift control corresponding to the road surface gradient). Since there is no significant effect, the process directly proceeds to step 10, and the speed change control for uphill or downhill using the gradient resistance mg · sin θ calculated in step 7 as having no braking force is executed.

In the speed change control for climbing downhill using the slope resistance mg · sin θ, it is not necessary to finely control the speed ratio in response to a slight change in the slope sin θ, and the speed of the slope sin θ varies. Since it is only sufficient, a slight error in the gradient resistance due to the generation of a small braking force does not cause a serious problem.
And, even during the braking operation as described above, when the actual braking force is sufficiently small, the gradient resistance is updated,
If the shift control for uphill or downhill is executed, for example, when the vehicle is running on a long downhill and the brake pedal is lightly applied for a long time, the brake operation may not be performed. Also, the update of the gradient resistance is detected, and the shift control corresponding to the change in the gradient resistance can be performed.

On the other hand, if the estimated braking force exceeds the predetermined value, a large error occurs in the detection result of the gradient resistance, and it may not be possible to properly execute the speed change control when going up or down a hill. In this case, step 10
, The shift control based on the gradient resistance is stopped (the detection result of the gradient resistance is invalidated), and the shift is performed with characteristics suitable for a normal flat road.

In the above embodiment, the shift control based on the detection result of the gradient resistance is stopped when the braking force exceeds a predetermined value. However, when the braking force exceeds the predetermined value, the detection of the gradient resistance is stopped. The same effect can be substantially obtained even if the configuration is stopped. In the above embodiment,
Although the description has been made using the four-speed automatic transmission, similar effects can be obtained by applying the present invention to a transmission other than the fourth-speed (third-speed or fifth-speed) transmission, and further to a continuously variable transmission.

[0038]

As described above, according to the vehicle control apparatus of the first aspect of the present invention, it is possible to simply perform the operation during the braking operation.
The control based on the slope resistance
Not based on whether the braking force exceeds a predetermined value.
The control based on the slope resistance
So, with your foot lightly on the brake pedal
Make sure that the braking force does not significantly affect the gradient detection
The control based on the slope resistance is stopped
No resistance, no slope resistance during braking
There is an effect that an opportunity for control according to is obtained.

[0039]

[0040]

[0041]

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of the present invention.

FIG. 2 is a system schematic diagram showing one embodiment of the present invention.

FIG. 3 is a flowchart showing shift control based on gradient resistance detection.

FIG. 4 is a flowchart showing a braking force estimation calculation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Automatic transmission 3 Fluid torque converter 4 Gear type transmission 5 Hydraulic actuator 7 Output shaft 13 Control unit 14 Throttle valve 15 Throttle sensor 16 Crank angle sensor 17 Air flow meter 18 Vehicle speed sensor 19 Turbine rotation sensor 20 Brake switch

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-231518 (JP, A) JP-A-62-113956 (JP, A) JP-A-5-71625 (JP, A) JP-A-61- 79056 (JP, A) JP-A-2-296067 (JP, A) JP-A-59-8698 (JP, A) JP-A-6-344802 (JP, A) JP-A-5-71633 (JP, A) JP-A-3-1822841 (JP, A) JP-A-3-258932 (JP, A) JP-A-4-138933 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 41/26 B60K 41/00 301 F16H 61/02

Claims (1)

(57) [Claims] 1. A gradient resistance calculating means for calculating a gradient resistance of a vehicle based on a driving force, an acceleration resistance, a rolling resistance and an air resistance, and a predetermined control of the vehicle based on the gradient resistance calculated by the gradient resistance calculating means. Control means for controlling the object; and a driving force, an acceleration resistance, a rolling resistance, an air resistance at a point in time when a predetermined time has elapsed after the start of the brake operation, and a gradient resistance calculated by the gradient resistance calculating means immediately before the brake operation. Braking force estimating means for estimating the braking force of the vehicle based on the control information, and control stopping means for stopping the control based on the gradient resistance by the control means when the braking force estimated by the braking force estimating means exceeds a predetermined value. A control device for a vehicle, comprising: