JPH08219269A - Torque ratio estimating device and line pressure control device of torque converter in automatic transmission - Google Patents

Abstract

PURPOSE: To estimate the torque ratio by calculating the pseudo speed ratio of a torque converter in the case where the gear ratio is assumed to be that before the speed change based on the engine speed to be detected during the speed change, the rotational speed of an automatic speed output shaft, and the gear ratio before the speed change. CONSTITUTION: An output shaft rotational speed sensor 11 as an output shaft rotational speed detecting means to detect the rotational speed of an output shaft 10 of an automatic transmission 2 is commonly used as a means to detect the vehicle speed. A control unit 6 automatically sets the speed change positions of the first speed through the fourth speed according to the throttle valve opening TVO and the vehicle speed VSP in the condition where a select bar is in the D-range based on the operation position signal of the select bar to be operated by a driver, and controls the speed change to control a gear type transmission 4 to the speed change position through a hydraulic actuator 5. At the same time, the torque ratio of a torque converter 3 during the speed change is estimated, and control is achieved so as to obtain the appropriate line pressure according to the input shaft torque of the transmission to be determined by the estimated torque ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for estimating a torque ratio of a torque converter during a shift of an automatic transmission with a torque converter, and a device for controlling a line pressure for gear shift control using the estimated torque ratio. Regarding

[0002]

2. Description of the Related Art In this type of automatic transmission, shift control is performed by controlling each shift element by a line pressure supplied to a hydraulic circuit. However, shock caused by a torque change between an engine side and an axle side due to a shift is performed. In order to reduce the above, it is necessary to adjust the line pressure to an appropriate value according to the engine torque.

Therefore, in the one disclosed in Japanese Patent Laid-Open No. 1-116636, the output torque of the engine is obtained from the fuel injection amount of the engine, and the output torque of the engine and the output torque of the torque converter, that is, the transmission input torque are calculated. Estimate and define a suitable line pressure. Further, the torque ratio of the torque converter is taken into consideration when defining the line pressure. Further, in the one disclosed in Japanese Patent Laid-Open No. 3-249468, the transmission input torque is calculated from the intake air flow rate, the engine rotation speed and the torque ratio of the torque converter.

[0004]

However, in the method disclosed in Japanese Patent Laid-Open No. 1-11636, the line pressure is referred from the map having the fuel injection amount and the engine rotation speed as parameters, and thus the ROM is used. Capacity becomes large, and the CPU becomes expensive. Further, there is a problem that it takes a lot of man-hours to match the oil pressure value map defined by the fuel injection amount and the engine rotation speed in consideration of the torque ratio.

Further, in the one disclosed in Japanese Patent Laid-Open No. 3-249468, a sensor for detecting the turbine rotation speed on the input side of the transmission is required because the speed ratio of the torque converter must be known in order to directly obtain the torque ratio. However, there was a problem that it was expensive. The present invention has been made in view of such conventional problems, and a torque ratio of a torque converter capable of estimating a torque ratio required for obtaining an appropriate line pressure without requiring an expensive device. It is an object to provide an estimation device.

[0006]

For this reason, the invention according to claim 1 detects the engine rotational speed in a torque converter of an automatic transmission connected to an output shaft of the engine as shown by a solid line in FIG. Engine rotation speed detection means, output shaft rotation speed detection means for detecting the rotation speed of the output shaft of the automatic transmission, gear ratio detection means for detecting the gear ratio of the automatic transmission,
Pseudo speed ratio of the torque converter when it is assumed that the gear ratio before shifting is maintained based on the engine rotation speed detected by each of the detecting means at the time of shifting and the rotation speed of the output shaft of the automatic transmission and the gear ratio before shifting. And a torque ratio estimating means for estimating the torque ratio of the torque converter during the shift based on the calculated pseudo speed ratio of the torque converter. .

Further, in the invention according to claim 2, the torque phase determining means for determining the torque phase at the time of shifting and the torque ratio estimating means calculate the pseudo speed ratio at the torque phase for the torque ratio at the torque phase. The estimation is performed based on the pseudo speed ratio calculated by the means.

The invention according to claim 3 is an inertia phase determining means for determining an inertia phase at the time of shifting, an extreme value detecting means for detecting an extreme value of the engine rotational speed during shifting, and the engine rotational speed A speed ratio change estimating means for estimating a speed ratio change during the inertia phase based on an extreme value; and the torque ratio estimating means, when the extreme value is detected for the torque ratio during the inertia phase, The pseudo speed ratio calculated by the speed ratio calculating means is estimated based on an average pseudo speed ratio obtained by correcting the pseudo speed ratio by the speed ratio change during the inertia phase estimated by the speed ratio change estimating means. To do.

The invention according to claim 4 is, as shown in FIG. 2, an engine output torque detecting means for detecting the output torque of the engine, and the torque according to any one of claims 1 to 4. Transmission input shaft torque for calculating the torque of the gear type transmission input shaft coupled to the output shaft of the torque converter based on the torque ratio of the torque converter estimated by the converter torque ratio estimation device and the output torque of the engine It is characterized by including a calculating means and a line pressure setting means for setting a line pressure for shift control based on the transmission input shaft torque.

[0010]

According to the first aspect of the present invention, by multiplying the output shaft rotation speed of the automatic transmission by the gear ratio before shifting, the pseudo torque converter output shaft is assumed to be maintained at the gear ratio before shifting. The rotational speed is obtained, and the pseudo speed ratio of the torque converter is obtained based on this and the engine rotational speed that is the rotational speed of the torque converter input shaft.

Then, the torque ratio of the torque converter is estimated based on the pseudo speed ratio. According to the second aspect of the present invention, since the substantial gear shift is not started and the gear ratio does not change during the torque phase, the pseudo speed ratio calculated during the torque phase matches the actual speed ratio. Therefore, the torque ratio can be calculated using the pseudo speed ratio as it is.

According to the third aspect of the present invention, during the inertia phase, the pseudo speed ratio differs from the actual speed ratio due to the change in the gear ratio due to the shift, but the change state (level) of the speed ratio.
Is related to the extreme value of the engine rotational speed immediately before the inertia phase, and therefore, the pseudo speed ratio calculated at the time of detecting the extreme value and the average pseudo speed during the inertia phase from the speed ratio change state estimated based on the extreme value. The speed ratio can be calculated, which allows the torque ratio during the inertia phase to be estimated.

According to the invention of claim 4, if the torque ratio of the torque converter is known, the torque converter output shaft torque, that is, the transmission input shaft torque can be calculated with respect to the engine output torque which is the input shaft torque of the torque converter. With the transmission input shaft torque, it is possible to set a line pressure that is capable of both mitigating torque shock during gear shifting and gear shift responsiveness.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 3 showing the configuration of the present embodiment, the automatic transmission 2 is connected to the output side of the engine 1. Automatic transmission 2
Is a torque converter 3 interposed on the output side of the engine 1,
The gear type transmission 4 connected through the torque converter 3 and the various transmission elements in the gear type transmission 4 are connected and
And a hydraulic actuator 5 for performing a releasing operation. The operating hydraulic pressure for the hydraulic actuator 5 is ON / OFF controlled via various electromagnetic valves (not shown).

Signals from various sensors are input to the control unit 6. As the various sensors, a throttle sensor 8 for detecting the opening TVO of the throttle valve 7 of the intake system of the engine 1 is provided. A crank angle sensor 9 is provided on the crankshaft of the engine 1 or a shaft that rotates in synchronization with the crankshaft. The signal from the crank angle sensor 9 is, for example, a pulse signal for each reference crank angle, and the engine rotation speed Ne is calculated from the period. Therefore, the crank angle sensor 9 corresponds to the engine rotation speed detecting means.

Further, an output shaft rotational speed sensor 11 is provided as an output shaft rotational speed detecting means for detecting the rotational speed No of the output shaft 10 of the automatic transmission 2. The output shaft rotation speed sensor 11 also serves to detect the vehicle speed. The control unit 6 controls the throttle valve opening TVO and the vehicle speed VSP when the select lever is in the D range based on the operation position signal of the select lever operated by the driver.
According to the above, the shift positions of the 1st to 4th speeds are automatically set, and the shift control is performed to control the gear type transmission 4 to the shift position via the hydraulic actuator 5. At the same time, the torque ratio of the torque converter 3 during the shift is changed. The control is performed such that the line pressure is estimated and the line pressure becomes appropriate according to the transmission input shaft torque determined by the estimated torque ratio.

The torque ratio estimation and line pressure setting routine of the torque converter according to this embodiment will be described below with reference to the flow charts of FIGS. Step (S in the figure
It is written. The same applies hereinafter) In 1, the engine rotation speed Ne calculated based on the signal from the crank angle sensor 9, the transmission output shaft rotation speed No detected by the output shaft rotation speed sensor 11, and the gear ratio CURGP are input.

In step 2, the speed ratio ETRATIO of the torque converter 3 is calculated by the following equation based on the above respective values. The function of step 2 constitutes the pseudo speed ratio calculating means. ETRATIO = No × CURGP / Ne In step 3, it is determined whether or not gear shifting (shift instruction output).

When it is determined in step 3 that the gear shift is in progress, the process proceeds to step 4 and it is determined whether the flag FLAGTS is set to 1 or not. This flag FLAG
TS is set to 1 during non-shift. When it is determined in step 4 that the flag FLAGTS is set to 1, that is, when the shift is started, the process proceeds to step 5, and when the shift is started, the speed ratio ETRATIO calculated in step 2 is calculated.
Is stored and held as the speed ratio ERARTIOT of the torque phase, the flag FLAGTS is reset to 0 in step 6, and then the process proceeds to step 7, and the flag FL is set in step 4.
If the AGTS is determined to be 0, then step 7 is performed as it is.
Go to.

In step 7, it is determined whether or not the shift is an upshift (shift to a high gear). If it is determined to be an upshift in step 7, the process proceeds to step 8, and the current engine speed Ne is compared with the maximum engine speed NEMAX updated and stored in the RAM. If Ne ≧ NEMAX, step 9 is performed. Then, the engine speed NEMAX is updated with the current engine speed Ne. The initial value of the maximum rotation speed NEMAX is set to 0, and the maximum rotation speed during shifting can be held by the update by the comparison.

In step 10, the current speed ratio ETRATIO calculated in step 2 is updated as an initial value ERATIOMAX of the speed ratio in the inertia phase described later. If it is determined that Ne <NEMAX in step 8, jump to steps 9 and 10
Proceed to 11.

In step 11, the maximum rotation speed NEM is set.
Speed ratio correction value DER from AX to inertia phase
AIO is obtained by searching the map. This correction value D
ERAIO is obtained in order to estimate the average speed ratio with respect to the speed ratio changing in the inertia phase, and as shown in the figure, the smaller the maximum rotation speed NEMAX immediately before the shift to the inertia phase, the smaller the speed ratio becomes. Since the amount of change is large, the correction amount DERAIO is set to a large value.

In step 12, the average speed ratio ERATIOI in the inertia phase is calculated by subtracting the correction amount DERAIO from the initial value ERATIOMAX calculated corresponding to the maximum rotation speed.
Since the correction amount DERAIO is set according to the change level of the speed ratio in the inertia phase, the function of step 11 at the time of upshifting includes the function of the speed ratio changing means.

In step 18, it is determined whether the torque phase or the inertia phase. This function constitutes the phase discrimination means. The start of the torque phase is determined by the start of the shift command, and here it is determined whether or not the shift to the inertia phase is made thereafter. There are various publicly known examples of the method of determining the inertia phase. For example, the method of detecting the rotation speed of the transmission input shaft (turbine shaft) proposed by the applicant of the present application has a relatively high accuracy. As a method that can be discriminated as described above, the pseudo rotation speed obtained by multiplying the transmission output shaft rotation speed by the gear ratio before shifting is corrected by the speed ratio of the torque converter before shifting, and the actual transmission output shaft rotation speed for determination. You can use a method that estimates the start of the inertia phase by comparing
(See Japanese Patent Application No. 6-217594).

If it is determined that the torque phase is reached, the routine proceeds to step 19, where the speed ratio E held at step 5
RATIOT is set as the speed ratio ERATIO used for torque ratio calculation in the torque phase. If it is determined to be in the inertia phase, the process proceeds to step 20, and in step 11, the speed ratio ERATIOI calculated and held when the engine speed Ne becomes maximum immediately before the transition to the inertia phase is set to the torque ratio in the inertia phase. Set it as the speed ratio ERATIO used for calculation.

In step 21, the torque ratio TRATIO with respect to the speed ratio ERATIO in the torque phase or inertia phase obtained as described above is obtained by searching the map. The function of this step 21 constitutes a torque ratio estimating means. In step 22, the transmission input torque TQTRIN is calculated by the following equation. TQTRIN = K · Q / Ne · TRATIO where K is a constant, Q is the intake air flow rate, and K · Q /
Ne corresponds to the engine output torque proportional to the cylinder intake air amount. Therefore, the function of step 22 constitutes the transmission input shaft torque detecting means and at the same time includes the function of the engine output torque detecting means.

In step 23, the line pressure P _L is retrieved from the map based on the transmission input torque TQTRIN calculated in step 21. The function of step 23 constitutes line pressure setting means. By doing so, the torque ratio can be estimated without using the torque sensor of the turbine shaft (transmission input shaft) of the torque converter, and the transmission input shaft torque obtained by using the estimated torque ratio. Accordingly, the line pressure for gear shift control can be controlled to an appropriate value that can satisfy the gear shift responsiveness while reducing the gear shift shock. FIG. 7 shows changes in each state quantity during upshift.

[0028]

As described above, according to the first aspect of the invention, the pseudo speed ratio of the torque converter is estimated without using the sensor for detecting the torque or the rotation speed of the torque converter output shaft, and the pseudo speed ratio is estimated. The torque ratio of the torque converter can be estimated based on the speed ratio.

According to the second aspect of the invention, during the torque phase, the torque ratio can be calculated by using the pseudo speed ratio calculated during the torque phase as it is.
According to the invention of claim 3, during the inertia phase, the average pseudo speed ratio during the inertia phase can be calculated from the speed ratio change state estimated based on the extreme value of the engine rotation speed immediately before the inertia phase. Can estimate the torque ratio during the inertia phase.

According to the fourth aspect of the present invention, the transmission input shaft torque can be calculated using the estimated torque converter torque ratio and the engine output torque. It is possible to set a line pressure that can achieve both relaxation and shift response.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration and a function of the invention according to claim 1.

FIG. 2 is a block diagram illustrating the configuration and function of the invention according to claim 4;

FIG. 3 is an overall system configuration diagram of an embodiment of the present invention.

FIG. 4 is a flowchart showing a preceding stage of a torque ratio estimation and line pressure setting routine of the above embodiment.

FIG. 5 is a flowchart showing the same middle stage.

FIG. 6 is a flowchart showing the latter part of the same.

FIG. 7 is a diagram showing changes in each state quantity during upshifting.

[Explanation of symbols]

 1 engine 2 automatic transmission 3 torque converter 6 control unit 8 throttle sensor 9 crank angle sensor 10 transmission output shaft 11 output shaft rotation speed sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area F16H 59:68

Claims (4)

[Claims] Claim: What is claimed is: 1. A torque converter for an automatic transmission connected to an output shaft of an engine, wherein an engine rotational speed detecting means for detecting an engine rotational speed and an output shaft rotational speed for detecting a rotational speed of an output shaft of the automatic transmission. Detection means, gear ratio detection means for detecting the gear ratio of the automatic transmission, and based on the engine rotation speed, the rotation speed of the automatic transmission output shaft, and the gear ratio before the shift, which are detected by the detection means at the time of shifting. And a pseudo speed ratio calculating means for calculating a pseudo speed ratio of the torque converter when the gear ratio before the shift is maintained, and a torque ratio of the torque converter during the shift based on the calculated pseudo speed ratio of the torque converter. A torque ratio estimating device for a torque converter, comprising: a torque ratio estimating means for estimating. 2. A torque phase determination means for determining a torque phase at the time of shifting, and the torque ratio estimation means has a pseudo speed ratio calculated by the pseudo speed ratio calculation means during the torque phase for the torque ratio at the torque phase. The torque ratio estimating device for a torque converter according to claim 1, wherein the torque ratio estimating device estimates the torque ratio. 3. An inertia phase discriminating means for discriminating an inertia phase at the time of shifting, an extreme value detecting means for detecting an extreme value of an engine rotational speed during shifting, and an inertia phase during the inertia phase based on the extreme value of the engine rotational speed. And a speed ratio change estimating means for estimating a change in speed ratio, wherein the torque ratio estimating means calculates the torque ratio during the inertia phase by the pseudo speed ratio calculating means when the extreme value is detected. 3. The pseudo speed ratio is estimated based on an average pseudo speed ratio obtained by correcting the pseudo speed ratio by the speed ratio change during the inertia phase estimated by the speed ratio change estimating means. A torque ratio estimating device for a torque converter according to item 1. 4. An engine output torque detecting means for detecting an output torque of the engine, and a torque ratio torque ratio estimated by the torque converter torque ratio estimating device according to any one of claims 1 to 4. And transmission input shaft torque calculation means for calculating the torque of the gear type transmission input shaft connected to the output shaft of the torque converter based on the output torque of the engine, and shift control based on the transmission input shaft torque. A line pressure control device for an automatic transmission, comprising: a line pressure setting means for setting a line pressure for a vehicle.