JPH0625656U - High altitude discrimination device for vehicles with automatic transmission - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to automatically correct the shift pattern by determining the high-altitude traveling state from the shift characteristics of the automatic transmission without using the atmospheric pressure sensor. [Configuration] The line pressure PL is learned and corrected so that the shift time t approaches a target shift time TRGTM. On the other hand, the deviation TOB (S) between the target shift time TRGTM and the actual shift time t
32) determines whether it is within a predetermined range (S33). When the deviation TOB is within the predetermined range, the preset reference line pressure PLSL is compared with the learned and corrected line pressure PL (S34). When the learned and corrected line pressure PL is smaller than the reference line pressure PLSL, the high-altitude traveling state of the vehicle is determined (S35), and the shift pattern is automatically corrected.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a high altitude discriminating device for a vehicle with an automatic transmission, and more particularly to a device for discriminating a high altitude traveling state of a vehicle based on a change in shift time in the automatic transmission.

[0002]

[Prior art]

 In a hydraulic automatic transmission for automobiles, the discharge pressure of an oil pump is regulated to obtain a line pressure, which is supplied to a hydraulic circuit, the hydraulic pressure of a hydraulic torque converter, and various transmission elements in a gear transmission. However, it is necessary to control the line pressure to an appropriate level according to the input torque to the automatic transmission.

Therefore, conventionally, there is a map in which an optimum line pressure is determined in advance corresponding to the opening degree of the throttle valve of the engine, and the line pressure adjusting actuator is driven based on this map to control the line pressure. (See Japanese Patent Laid-Open No. 62-9054, etc.). Further, the automatic transmission for a vehicle is provided with a shift pattern (shift map) set in advance corresponding to the vehicle speed and the throttle valve opening of the engine, and based on the detected values of the vehicle speed and the throttle valve opening, The gear position is determined by referring to the gear shift pattern, and the gear shift operation is performed in the transmission so as to match the determined gear position (see Japanese Patent Laid-Open No. 61-257332, etc.).

[0004]

[Problems to be solved by the device]

 By the way, although the throttle valve opening is used as a parameter that represents the output torque of the engine, the air density becomes low when driving at high altitudes, and the engine output torque actually obtained for the same throttle valve opening becomes low. Therefore, if the characteristics of the line pressure control and automatic gear shift control are adapted to low-level running conditions, a shift shock may occur due to excessive line pressure setting, or gear shifting to an inappropriate gear position may occur. Problems such as reduced power performance occur.

As a means for solving such a problem, an altitude sensor is used to make a high altitude determination, and the characteristics of the line pressure control and the automatic shift control are adapted to a change in air density. However, there was a problem that providing an atmospheric pressure sensor would increase the cost. The present invention has been made in view of the above problems, and provides a device capable of discriminating a high-altitude running state from a change in shift characteristics of an automatic transmission. The purpose is to be able to change the characteristics according to the altitude change without using the atmospheric pressure sensor.

[0006]

[Means for Solving the Problems]

 Therefore, the highland discriminating apparatus for a vehicle with an automatic transmission according to the present invention is configured as shown in FIG. 1 or 2. In FIG. 1, the shift time detecting means detects the changing time of the automatic transmission mounted on the vehicle, and the high altitude discriminating means based on the shift time indicates the shift time detected by the shifting time detecting means which is a preset reference. When the time is shorter than the time, the high-altitude driving condition of the vehicle is determined.

On the other hand, in FIG. 2, the hydraulic control means for controlling the hydraulic pressure supplied to the hydraulic circuit for controlling the engagement elements of the automatic transmission so that the shift time detected by the shift time detecting means approaches the target time. The high-altitude determination means based on hydraulic pressure determines the high-altitude traveling state of the vehicle when the hydraulic pressure controlled by the hydraulic pressure control means is lower than a preset reference hydraulic pressure.

[0008]

[Action]

 According to this structure, if the control of the fastening elements at the time of shifting is not able to cope with the change in the engine output torque due to the change in altitude, the engine output torque will decrease as the air density decreases due to the high altitude running of the vehicle. , The shift time becomes shorter due to the decrease of the input torque. Therefore, the high-speed running state of the vehicle can be determined based on the fact that the shift time is shorter than the reference time.

Further, when the hydraulic pressure is controlled so that the shift time matches the target time, if the engine output torque decreases, the shift time shortens. Since it is necessary to lower the hydraulic pressure required for higher altitudes, the required hydraulic pressure will decrease.Therefore, when the hydraulic pressure controlled to maintain the target time is smaller than the reference hydraulic pressure, it means that the vehicle is traveling at high altitude. Can be distinguished.

[0010]

【Example】

 An embodiment of the present invention will be described below. In FIG. 3, which schematically shows the system configuration of one embodiment, an automatic transmission 2 is provided on the output side of an 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, a gear type transmission 4 connected via the fluid type torque converter 3, and a gear type transmission 4 in the gear type transmission 4. A hydraulic actuator 5 for connecting and disconnecting various speed change elements.

The operating hydraulic pressure for the hydraulic actuator 5 is controlled via various electromagnetic valves, but here only the electromagnetic valves 6A and 6B for shifting for automatic shifting are shown. Reference numeral 7 is 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 a hydraulic pressure for the hydraulic torque converter 3 and the hydraulic actuator 5, and a pilot valve 9 and an electromagnetic valve are used. A valve 10, a pressure modifier valve 11 and a pressure regulator valve 12 are provided.

The pilot valve 9 regulates the discharge pressure of the oil pump 8 to the pilot pressure acting on the electromagnetic valve 10. The electromagnetic valve 10 regulates the pilot pressure to the throttle pressure according to the operating condition, and the pressure modifier valve 11 regulates the pilot pressure to the pressure modifier pressure according to the throttle pressure and 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 hydraulic torque converter 3 and the hydraulic actuator 5.

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 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 crankshaft of the engine 1 or a shaft (camshaft) that rotates in synchronization with the crankshaft. The engine rotation speed Ne is calculated from a signal from the crank angle sensor 16. It is like this.

Further, a turbine sensor 17 for extracting a rotation signal Nt (an input shaft rotation speed of the gear transmission 4) from a turbine liner of the fluid torque converter 3 or an input shaft of the gear transmission 4 is provided. Further, a vehicle speed sensor 18 for detecting the vehicle speed VSP by detecting the rotation speed No of the output shaft 7 of the automatic transmission 2 (the output shaft rotation speed of the gear type transmission 4) is provided.

The control unit 13 performs shift control and line pressure control in the automatic transmission 2 having the above configuration. The automatic shift control is performed in accordance with the operating position of the select lever (not shown) operated by the driver. Especially when the select lever is in the D range, the 1st to 4th speeds are set according to the throttle valve opening TV O and the vehicle speed VSP. Is automatically set, the on / off combination of the electromagnetic valves 6A and 6B for shifting is controlled, and the gear type transmission 4 is controlled to the gear position via the hydraulic actuator 5.

The line pressure control refers to a map in which the optimum line pressure is stored in advance in accordance with the throttle valve opening TVO and the gear position (type of gear change during a gear shift), and the line pressure obtained by searching from the map is referred to. In order to obtain it, the electromagnetic valve 10 is drive-controlled. Here, an embodiment for discriminating the high-altitude traveling state from the shift time t in the shift control performed based on the line pressure PL will be described with reference to the flowcharts of FIGS. 4 and 5. In this embodiment, the control unit 13 is provided with the software as the shift time detecting means and the function as the high altitude discriminating means based on the shift time as shown in the flow charts of FIGS.

The flowchart of FIG. 4 shows a program for detecting the shift time t. In the present embodiment, the timing at which the engine speed Ne drops at a predetermined rate or more after the shift request is made is detected as the timing at which the shift actually starts, and then the gear ratio = the output shaft of the transmission. The time when the rotation speed No (vehicle speed VSP) / turbine rotation speed Nt crosses a predetermined level set for each type of shift is detected as the end of the shift operation, and the shift time is based on the start / end points of the shift operation. Measure t (see Figure 8). However, the method for detecting the shift start and end points is not limited to the above, and for example, the shift end may be detected based on the speed ratio of the hydraulic torque converter 3.

First, in step 1 (denoted as S1 in the drawing; the same applies hereinafter), the engine speed Ne detected most recently after the shift request is made is compared with the maximum speed Nemax whose initial value is zero. . When the engine rotation speed Ne is equal to or higher than the maximum speed Nemax, the rotation speed Ne detected this time in step 2 is set to the maximum speed Nemax, and then the routine proceeds to step 3.

On the other hand, when it is determined that the engine rotation speed Ne is lower than the maximum speed Nemax, the routine jumps from step 2 to step 3. In step 3, the value obtained by subtracting the latest rotation speed Ne from the maximum speed Nemax is compared with a positive predetermined value TRGNE to determine whether or not the engine rotation speed Ne has dropped at a predetermined rate or more. The time point when it is determined that Nemax-Ne ≧ TRGNE is set as the shift start point.

That is, as shown in FIG. 8, the increase in the rotation speed Ne after the shift request is detected, the maximum speed immediately before the rotation speed falls is set to Nemax, and the change in the rotation speed Ne starts to decrease. After that, the point that falls below a predetermined level is used as the actual shift start point. When the shift start is determined in step 3, the process proceeds to step 4 and a timer for measuring the shift time t is started.

Then, in the next step 5, the gear ratio of the transmission (= output shaft rotational speed No (vehicle speed VSP) / input shaft rotational speed Nt (turbine rotational speed)) is set for each type of gear shifting. It is determined whether or not the level SFTFIN is crossed (whether or not the level is above a predetermined level SFTFIN when shifting up). If it is determined that the gear ratio (No / Nt) has crossed the predetermined level SFTFIN, this is considered to be the end of the shift and the process proceeds to step 6 where the timer started when the shift start is determined. Stop.

Next, in step 7, the time measured by the timer is set to the shift time t. The flowchart of FIG. 5 shows a program for performing highland discrimination based on the measured shift time t. First, in step 11, the measurement result of the shift time t based on the flowchart of FIG. 4 is input.

In the next step 12, the input shift time t is compared with the reference time ATPTM preset for each type of shift. Here, when the actual shift time t is shorter than the reference time ATPTM, the line pressure based on the throttle valve opening TVO is set to the true input torque due to the decrease in engine output torque due to the decrease in air density. It is estimated that the required level is higher than the required level, and the process proceeds to step 13 to determine the high-altitude traveling state of the vehicle.

In this way, when the high-altitude traveling state is determined, the set level of the line pressure is lowered as a whole, the shift pattern is changed so that the shift is performed at a higher vehicle speed side, and In engine control, it corrects parameters that are affected by altitude changes (such as control constants for idle rotation feedback control). According to the above-described embodiment, the high-altitude traveling state of the vehicle can be determined without using an expensive sensor such as an atmospheric pressure sensor, and thus the characteristics of the line pressure control and the shift control in the automatic transmission can be adapted to the high-altitude traveling state. It is possible to switch to the characteristics to be used.

By the way, the shift time t detected as described above is compared with a target shift time preset for each type of shift, and the actually measured shift time t approaches the target time. As described above, when the line pressure learning function that corrects the initially set line pressure is provided, for example, when gradually increasing the altitude from lowlands, the line pressure correction function can be used to change the altitude. Correspondingly, the line pressure is sequentially corrected, and the shift time t becomes stable near the target time, and it is not possible to determine the high altitude traveling state from the shift time t.

Therefore, an example of highland discrimination in the case where the above-described line pressure (hydraulic pressure) learning function is provided will be described below according to the flow charts of FIGS. 6 and 7 together with the state of line pressure learning. In the present embodiment, the control unit 13 is provided with the functions of the shift time detecting means, the hydraulic pressure controlling means, and the high altitude discriminating means by hydraulic pressure by software.

The flow chart of FIG. 6 shows the state of line pressure learning. First, in step 21, the shift time t is measured as shown in the flow chart of FIG. In step 22, the deviation T between the target shift time TRGTM and the measured shift time t is calculated.

Then, in step 23, based on the deviation T, the correction amount LNPL of the line pressure PL is set so that the actual shift time t approaches the target speed change time TRGTM. That is, when the shift time t is longer than the target, the correction amount LNPL is set as a positive value in order to increase the line pressure PL, and conversely, when the shift time t is shorter than the target, The correction amount LNPL is set as a negative value in order to reduce the line pressure PL.

In the next step 24, the line pressure PL up to that time is corrected based on the set correction amount LNPL, and the stored data is updated with the correction result as a new line pressure PL. The program shown in the flowchart of FIG. 7 shows a state of highland discrimination when the learning control of the line pressure PL is performed as described above.

In the flowchart of FIG. 7, in step 31, the measurement result of the shift time t is input, and in the next step 32, the deviation TOB between the target time TRGTM and the actual shift time t is obtained. Then, in step 33, it is confirmed whether or not the deviation TOB is within a predetermined range and is controlled to the substantially target shift time TRGTM by the line pressure learning.

Here, when the deviation TOB is within the predetermined range, the routine proceeds to step 34, where the preset reference line pressure PLSL and the learned set line pressure PL are compared. The reference line pressure PLSL is set to a level at which the line pressure PL (learned and corrected line pressure) does not drop even when there is a possible variation in individual vehicles in lowland traveling, and the vehicle moves to a highland. Then, the actual line pressure PL is set to be lower only after the line pressure PL needs to be significantly reduced and corrected.

Therefore, when the line pressure PL learned to obtain the target shift time is lower than the reference line pressure PLSL, the engine output corresponding to the throttle valve opening TVO due to the decrease in the air density due to high altitude traveling. It is estimated that the torque has decreased and the line pressure PL required to obtain the target shift time TRGTM has decreased significantly, and the routine proceeds to step 35, where the high-altitude traveling state of the vehicle is determined.

In this case, the line pressure PL is adjusted to a level commensurate with the high-altitude traveling state by feedback control to the target shift time, so when the high-altitude traveling state is determined, other shift pattern changes, etc. Should be done. In the above embodiment, the low-altitude traveling state and the high-altitude traveling state are discriminated on / off, but the altitude is discriminated in a plurality of stages based on the shift time t or the level of the learned line pressure PL. It is also possible to let.

[0034]

[Effect of device]

 As described above, according to the present invention, the change in the engine output torque due to the change in altitude is detected based on the shift time in the automatic transmission or the hydraulic pressure controlled to keep the shift time at the target time. As a result, the vehicle's high-altitude running state is determined.For example, the gear shift pattern of an automatic transmission can be changed to one suitable for high-altitude running state without using a high-altitude determination sensor such as an atmospheric pressure sensor. The effect is that you can do it.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing the basic configuration of the present invention.

FIG. 3 is a system schematic diagram showing an embodiment of the present invention.

FIG. 4 is a flowchart showing measurement of shift time.

FIG. 5 is a flowchart showing highland discrimination based on shift time.

FIG. 6 is a flowchart showing learning control of line pressure.

FIG. 7 is a flowchart showing highland discrimination using a line pressure learning value.

FIG. 8 is a time chart showing how the shift time is measured.

[Explanation of symbols]

 1 Engine 2 Automatic Transmission 3 Fluid Torque Converter 4 Gear Transmission 5 Hydraulic Actuator 7 Output Shaft 8 Oil Pump 9 Pilot Valve 10 Electromagnetic Valve 11 Pressure Modifier Valve 12 Pressure Regulator Valve 13 Control Unit 14 Throttle Valve 15 Throttle Sensor 16 Crank angle sensor 17 Turbine sensor 18 Vehicle speed sensor

Claims (2)

[Scope of utility model registration request] 1. A shift time detecting means for detecting a shift time in an automatic transmission combined with an engine mounted on a vehicle, and a shift time detected by the shift time detecting means is shorter than a preset reference time. A highland discriminating apparatus for a vehicle with an automatic transmission, comprising: a highland discriminating means based on shift time for discriminating a highland traveling state of the vehicle. 2. A shift time detecting means for detecting a shift time in an automatic transmission combined with an engine mounted on a vehicle, and an automatic shift so that the shift time detected by the shift time detecting means approaches a target time. A high-altitude determination device for a vehicle with an automatic transmission, comprising: a hydraulic control means for controlling a hydraulic pressure supplied to a hydraulic circuit for controlling a fastening element of the machine, wherein the hydraulic pressure controlled by the hydraulic control means is preset. A highland discriminating apparatus for a vehicle with an automatic transmission, comprising a highland discriminating means based on a hydraulic pressure for discriminating a highland traveling state of the vehicle when it is smaller than the reference hydraulic pressure.