JP3980090B2 - Gradient resistance detection device for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle gradient resistance detection apparatus, and more particularly to an apparatus capable of correctly detecting gradient resistance even during braking from a vehicle equation of motion.
[0002]
[Prior art]
In general, an automatic transmission for a vehicle includes a shift map in which a gear position is set in advance corresponding to an accelerator opening and a vehicle speed, and the gear position is generally determined with reference to the shift map. However, the shift pattern is set on the assumption that the vehicle travels on a general flat road. For example, when climbing or descending, an appropriate shift characteristic (speed ratio) may not be obtained.
[0003]
Therefore, the gradient of the road surface on which the vehicle is traveling (grade resistance), the driving force, the air resistance, rolling resistance, determined on the basis of the acceleration resistance, such as by changing the shift pattern based on the gradient resistance, proper Various automatic shift controls have been proposed in which the shift characteristics can be obtained during uphill / downhill (see Japanese Patent Publication No. 59-8698).
[0004]
[Problems to be solved by the invention]
However, when determining the vehicle's gradient resistance, if the brake is operated, the engine output torque will apparently decrease in accordance with the braking force of the brake. As a result, the gradient resistance is erroneously detected, and there is a possibility that the speed change characteristic cannot be appropriately controlled.
[0005]
As a countermeasure technique for such a problem, Japanese Patent Application Laid-Open No. 5-71625 discloses a method for stopping the uphill / downhill control of the transmission based on the gradient detection result when the brake is operated. Japanese Patent Application Laid-Open No. 61-79056 discloses a technique for avoiding calculation of running resistance during a brake operation by calculating the running gradient immediately after the vehicle starts running. Furthermore, Japanese Patent Laid-Open No. 2-296067 discloses that when a brake operation is performed while gear shift control suitable for traveling on an uphill road is performed, the previous gear ratio is maintained while the brake operation is performed. Thus, the traveling resistance is erroneously detected in accordance with the brake operation, thereby avoiding improper shift control.
[0006]
By the way, none of the above-described countermeasure techniques execute the shift control based on the new detection of the gradient resistance during the brake operation. For this reason, for example, when traveling on a long downhill, if the state where the brake is lightly applied continues for a long time, even if the road surface condition (road surface gradient) changes during the relatively long brake operation period, Therefore, there is a risk that the speed change control corresponding to the change in the road surface condition is not performed at all, and the expected effect of making the speed change characteristic on the uphill / downhill based on the gradient resistance suitable cannot be exhibited at all. there were.
[0007]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an opportunity for detecting gradient resistance during brake operation while avoiding erroneous detection of gradient resistance accompanying brake operation. And
[0008]
[Means for Solving the Problems]
Therefore, the invention described in claim 1 is configured as shown in FIG.
In FIG. 1, the driving force calculating means calculates the driving force of the vehicle, and the acceleration resistance calculating means calculates the acceleration resistance of the vehicle.
On the other hand, the brake oil pressure detecting means detects the brake oil pressure in a hydraulic brake device provided in the vehicle.
[0009]
The braking force estimating means estimates the braking force of the brake based on the brake hydraulic pressure detected by the brake hydraulic pressure detecting means. Here, the gradient resistance calculating means calculates the gradient resistance based on at least the driving force, acceleration resistance, and brake braking force. According to this configuration, the braking force estimated from the brake hydraulic pressure is taken into account when calculating the gradient resistance, so there is no need to stop calculating the gradient resistance during braking, and the gradient resistance can be detected accurately during braking. it can.
[0010]
The invention according to claim 2 is configured as shown in FIG.
2, in place of the brake hydraulic pressure detection means shown in FIG. 1, pedal depression pressure detection means for detecting the depression force of the brake pedal in the brake device provided in the vehicle is provided, and the pedal depression pressure detection means detects the pedal depression pressure detection means. Based on the depression force of the brake pedal, the braking force estimation means estimates the braking force of the brake.
[0011]
According to such a configuration, since the braking force estimated from the depression force of the brake pedal is taken into account in calculating the gradient resistance, it is not necessary to stop the calculation of the gradient resistance during braking, and the gradient resistance is accurately calculated during braking. Can be detected.
In the invention according to claim 3, the gradient resistance calculating means is
The gradient resistance is calculated as gradient resistance = drive force−acceleration resistance−brake braking force.
[0012]
According to this configuration, by subtracting the brake braking force from the driving force, it can be avoided that the brake braking force component is added to the gradient resistance and detected.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
In FIG. 3 showing the system configuration of the embodiment, an automatic transmission 2 is provided on the output side of an internal combustion engine 1 mounted on a vehicle (not shown). The automatic transmission 2 includes a fluid type torque converter 3 interposed on the output side of the engine 1, a gear type transmission 4 connected via the fluid type torque converter 3, and various types in the gear type transmission 4. And a hydraulic actuator 5 for performing coupling / release operation of the speed change element. The hydraulic pressure for the hydraulic actuator 5 is controlled via various electromagnetic valves, but only the shift electromagnetic valves 6A and 6B for automatic transmission are shown here. Reference numeral 7 denotes an output shaft of the automatic transmission 2.
[0014]
Here, an oil pump 8 driven by the input shaft of the gear-type transmission 4 is used to obtain a line pressure that is an operating hydraulic pressure for the fluid torque converter 3 and the hydraulic actuator 5, and a pilot valve 9, an electromagnetic valve 10, a pressure modifier valve 11 and a pressure regulator valve 12 are provided.
[0015]
The pilot valve 9 regulates the discharge pressure of the oil pump 8 to a pilot pressure that acts on the electromagnetic valve 10. The electromagnetic valve 10 is duty-controlled as will be described later, and the pilot pressure is adjusted to the throttle pressure according to the operating conditions, and the pressure modifier valve 11 is adjusted to the pressure modifier pressure corresponding to the throttle pressure, Acts on the pressure regulator valve 12. The pressure regulator valve 12 regulates the oil pump discharge pressure to a line pressure proportional to the pressure modifier pressure, and sends it to a hydraulic circuit such as the fluid type torque converter 3 and the hydraulic actuator 5.
[0016]
Signals from various sensors are input to the control unit 13. As the various sensors, a potentiometer type throttle sensor 15 for detecting the opening degree TVO of the throttle valve 14 of the intake system of the engine 1 is provided. A crank angle sensor 16 is provided on the 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, and the engine speed Ne is calculated based on the cycle.
[0017]
Further, a hot-wire air flow meter 17 for detecting the intake air flow rate Q is provided in the intake system of the engine 1. From the intake air flow rate Q detected by the air flow meter 17 and the engine rotational speed Ne calculated based on the signal of the crank angle sensor 16, a basic fuel serving as a basis for calculating the fuel injection amount by the electronically controlled fuel injection device The injection amount Tp = K × Q / Ne (K is a constant) is calculated.
[0018]
Further, a vehicle speed sensor 18 that detects the vehicle speed VSP by detecting the rotational speed No of the output shaft 7 of the automatic transmission 2 is provided.
Further, a turbine rotation sensor 19 for detecting the turbine rotation speed Nt in the fluid type torque converter 3 is provided.
Further, a hydraulic pressure sensor 20 is provided as a brake hydraulic pressure detecting means for detecting a brake hydraulic pressure in a hydraulic brake device (not shown) of the vehicle.
[0019]
The control unit 13 integrally includes a unit for engine control (fuel injection and ignition timing control) and a unit for automatic transmission control, and the units can exchange signals with each other.
The automatic shift control unit mainly performs shift control and line pressure control. Automatic shift control is performed in accordance with the operation position of a select lever (not shown) operated by the driver, and in particular when the select lever is in the D range, a 1st to 4th speed shift is performed according to the throttle valve opening TVO and the vehicle speed VSP. The position is automatically set, the on / off combination of the shift electromagnetic valves 6A and 6B is controlled, and the gear type transmission 4 is controlled to the shift position via the hydraulic actuator 5.
[0020]
Here, in the combination of the automatic transmission 2 and the engine 1 as described above, the shift pattern, the fastening force of the lock-up clutch, and the like are determined according to the running resistance (particularly the gradient resistance) of the vehicle on which the engine 1 is mounted. It is desirable to change.
Therefore, the control unit 13 calculates a road surface gradient (gradient resistance) as shown in the flowchart of FIG. 4, and according to the road surface gradient (gradient resistance), a shift pattern (speed ratio) and lock-up in the automatic transmission. The fastening force of the clutch is changed.
[0021]
Note that the control unit 13 has functions as driving force calculating means, acceleration resistance calculating means, braking force estimating means, and gradient resistance calculating means as shown in the flowchart of FIG.
In the flowchart of FIG. 4, in step 1 (indicated by S1 in the figure, the same applies hereinafter), the driving force F is calculated.
[0022]
Specifically, the turbine torque Tt is obtained based on the throttle valve opening TVO detected by the throttle sensor 15 and the turbine rotational speed Nt detected by the turbine rotation sensor 19, and the turbine torque Tt and the gear ratio in the transmission are determined. Using i, the final gear ratio if, and the conversion coefficient k, the driving force F is calculated as F = Tt × i × if × k.
[0023]
In step 2, the acceleration resistance is calculated. The acceleration resistance can be obtained as a multiplication value of the acceleration a and the standard vehicle weight m stored in advance by obtaining the acceleration a from the rate of change of the vehicle speed VSP detected by the vehicle speed sensor 18 (acceleration resistance). = Ma).
In step 3, the sum RL of the rolling resistance and air resistance of the vehicle is set based on the vehicle speed VSP detected by the vehicle speed sensor 18.
[0024]
In step 4, the brake hydraulic pressure detected by the hydraulic sensor 20 is read.
In step 5, the brake hydraulic pressure is converted into a braking force FB based on a preset table, and a braking force corresponding to the brake hydraulic pressure is estimated.
In step 6, the slope resistance mg · sin θ is
mg · sin θ = F-ma-RL-FB
Calculate as
[0025]
In step 7, the shift pattern is changed on the basis of the gradient resistance mg · sin θ calculated in step 6 or the road surface gradient θ obtained from the gradient resistance mg · sin θ. Automatic shift to the gear ratio.
If the configuration is such that the braking force is estimated and the gradient resistance is detected as described above, the gradient resistance can be correctly detected even during braking, and the vehicle can be controlled in a wide range according to the gradient resistance. The performance can be improved.
[0026]
The control based on the calculated gradient resistance mg · sin θ or the road surface gradient θ is not limited to the change of the shift pattern. For simplicity, the rolling resistance and air resistance RL may be omitted, and the slope resistance may be calculated as mg · sin θ = F−ma−FB.
In the embodiment shown in the flowchart of FIG. 4, the brake braking force is estimated based on the brake hydraulic pressure. However, the brake braking force may be estimated based on the depression pressure of the brake pedal.
[0027]
In the case of such a configuration, as shown in FIG. 3, a pedal pressure sensor 21 is provided as pedal depression force detecting means for detecting the brake pedal depression pressure, and the gradient resistance is calculated as shown in the flowchart of FIG.
In the flowchart of FIG. 5, each step other than steps 4A and 5A is the same as the flowchart of FIG. 4, and only steps 4A and 5A will be described.
[0028]
In step 4A, the brake pedal depression pressure detected by the depression pressure sensor 21 is read.
In step 5A, the brake pedal depression pressure is converted into a braking force FB based on a preset table, and a braking force corresponding to the brake pedal depression pressure is estimated.
Then, the gradient resistance mg · sin θ is calculated using the braking force FB estimated from the brake pedal depression pressure, the driving force F, the acceleration resistance ma, and the rolling / air resistance RL.
[0029]
【The invention's effect】
As described above, according to the first or second aspect of the invention, since the gradient resistance is calculated taking into account the brake braking force estimated from the brake hydraulic pressure or the depression pressure of the brake pedal, the calculation of the gradient resistance is stopped during braking. In addition, there is an effect that the gradient resistance can be accurately detected during braking.
[0030]
According to the invention described in claim 3, by subtracting the brake braking force from the driving force, there is an effect that the gradient resistance can be accurately detected without adding the brake braking force to the gradient resistance.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a basic configuration of an apparatus according to claim 1;
FIG. 2 is a block diagram showing a basic configuration of the apparatus according to claim 2;
FIG. 3 is a system schematic diagram of the embodiment.
FIG. 4 is a flowchart showing a first embodiment of shift control based on gradient resistance detection.
FIG. 5 is a flowchart showing a second embodiment of shift control based on gradient resistance detection.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Automatic transmission 3 Fluid type 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 Hydraulic sensor
21 Treading pressure sensor

Claims (3)

Driving force calculating means for calculating the driving force of the vehicle, acceleration resistance calculating means for calculating the acceleration resistance of the vehicle, brake oil pressure detecting means for detecting the brake oil pressure in the hydraulic brake device provided in the vehicle, and the brake oil pressure Braking force estimating means for estimating the braking force of the brake based on the brake hydraulic pressure detected by the detecting means; and gradient resistance calculating means for calculating the gradient resistance based on at least the driving force, acceleration resistance and brake braking force. An apparatus for detecting a gradient resistance of a vehicle, comprising: Driving force calculating means for calculating the driving force of the vehicle, acceleration resistance calculating means for calculating the acceleration resistance of the vehicle, pedal depression pressure detecting means for detecting the depression force of the brake pedal in the brake device provided in the vehicle, and the pedal depression pressure Braking force estimating means for estimating the braking force of the brake based on the depression force of the brake pedal detected by the detecting means; and gradient resistance calculating means for calculating the gradient resistance based on at least the driving force, acceleration resistance and brake braking force; A vehicle gradient resistance detecting device comprising: 3. The vehicle gradient resistance detection apparatus according to claim 1, wherein the gradient resistance calculation unit calculates the gradient resistance as gradient resistance = driving force-acceleration resistance-brake braking force.

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