JP3608971B2 - Solenoid temperature estimation device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a solenoid temperature estimation device that estimates the temperature of a solenoid (particularly a linear solenoid) from an environmental temperature.
[0002]
[Prior art]
In a vehicular automatic transmission, in particular, in a direct-acting automatic transmission in which a hydraulic pressure supplied to each friction engagement element (clutch, brake) is controlled to a target hydraulic pressure by each solenoid valve, the solenoid valve is set. When controlling the linear solenoid, the resistance value changes depending on the temperature of the solenoid, and the characteristics of the command duty value and current value change. It is necessary to correct the value, and generally, the ambient temperature (oil temperature) is detected and substituted.
[0003]
[Problems to be solved by the invention]
However, the environmental temperature (oil temperature) and the solenoid temperature do not necessarily match, and the change in the solenoid temperature is larger than the change in the environmental temperature. Specifically, the solenoid temperature is higher in the high temperature range of the environmental temperature, and the solenoid temperature is lower in the low temperature range of the environmental temperature.
[0004]
Therefore, it is difficult to correct appropriately according to the actual solenoid temperature only by correcting the characteristics of the solenoid according to the environmental temperature.
Therefore, it is desirable to directly detect the solenoid temperature. However, providing a special temperature sensor not only requires a mounting space but also increases costs. In particular, a direct-acting automatic transmission is not realistic because it has a large number of solenoids.
[0005]
The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a solenoid temperature estimation device that can estimate a solenoid temperature from an environmental temperature with a practically sufficient accuracy.
[0006]
[Means for Solving the Problems]
For this reason, in the invention according to claim 1, as shown in FIG. 1, the environmental temperature detecting means for detecting the environmental temperature, the solenoid current detecting means for detecting the current flowing through the solenoid, and the heat generation of the solenoid based on the current. Solenoid heat generation calculation means for calculating the amount equivalent value and solenoid temperature calculation means for calculating the solenoid temperature based on the environmental temperature and the heat generation amount equivalent value are provided to constitute a solenoid temperature estimation device. Here, the solenoid temperature calculation means calculates the solenoid temperature by adding the calorific value equivalent value to the environmental temperature in the high temperature range of the environmental temperature, and calculates the solenoid temperature from the environmental temperature in the low temperature range of the environmental temperature. A solenoid temperature is calculated by subtracting a predetermined value Tc, and the ambient temperature is directly used as the solenoid temperature in an intermediate temperature range between the high temperature range and the low temperature range.
The predetermined value Tc may be a constant (Claim 4), but may be set according to the environmental temperature, and may be increased as the environmental temperature is lower (Claim 5). The predetermined value Tc may be a value obtained by subtracting the calorific value equivalent value from a constant TC.
[0007]
The invention according to claim 2 is characterized in that the solenoid is used for hydraulic control, and the environmental temperature detecting means detects the temperature of the hydraulic oil (oil temperature).
[0008]
The invention according to claim 3 is characterized in that the solenoid heat generation amount calculation means calculates a heat generation amount equivalent value by referring to a table in which a heat generation amount equivalent value for the solenoid current is previously determined and stored. And
[0012]
【The invention's effect】
According to the first aspect of the invention, there is an effect that the solenoid temperature can be accurately estimated from the environmental temperature and the calorific value corresponding to the current flowing through the solenoid without adding a special sensor. can get.
Also, the solenoid temperature is calculated by adding the value corresponding to the amount of heat generated by the solenoid to the environmental temperature in the high temperature range, and the solenoid temperature is calculated by subtracting a predetermined value from the environmental temperature in the low temperature range. In the middle temperature range of the environmental temperature, the solenoid temperature is used as it is, so that the solenoid temperature is higher in the high temperature range and the solenoid temperature is lower in the low temperature range. Based on this knowledge, the solenoid temperature can be accurately and easily estimated.
[0013]
According to the second aspect of the present invention, in the case of a solenoid for hydraulic control, it is possible to accurately capture the environmental temperature by detecting the temperature of the hydraulic oil (oil temperature).
[0014]
According to the invention which concerns on Claim 3, when calculating the calorific value equivalent of a solenoid, it can calculate simply by using a predetermined table.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
FIG. 2 is a system diagram of a vehicular automatic transmission to which the solenoid temperature estimating apparatus according to the present invention is applied. The output torque of the engine 1 is transmitted to the drive wheels via the automatic transmission 2.
[0018]
The automatic transmission 2 has a configuration in which a shift is performed by controlling the supply of operating hydraulic pressure to a friction engagement element such as a clutch and a brake by a solenoid valve unit 3. , Reverse clutch, high clutch, band brake, low & reverse brake, forward clutch.
[0019]
Further, the automatic transmission 2 is configured to execute a shift (so-called clutch-to-clutch shift) in which at least two friction engagement elements are simultaneously engaged and released by hydraulic control without using a one-way clutch. ing.
[0020]
Therefore, as shown in FIG. 3, for each friction engagement element 20, a solenoid valve 30 connected to a line pressure (source pressure) source and a drain is provided, and a linear solenoid constituting each solenoid valve 30 is connected to the linear solenoid. By controlling the duty (drive current), the hydraulic pressure applied to each friction engagement element 20 is controlled.
[0021]
The control unit 4 that controls the solenoid valve unit 3 (each solenoid valve 30) stores a table indicating the correlation between the drive current of each solenoid valve 30 and the hydraulic pressure. When the target hydraulic pressure is calculated, the target hydraulic pressure is calculated. Is obtained by table conversion, and the drive current of each solenoid valve 30 is controlled.
[0022]
The drive current is controlled by duty. Here, there is a temperature dependency between the duty and the drive current. Therefore, it is necessary to correct the duty according to the temperature of the solenoid. For this purpose, the solenoid temperature estimation device according to the present invention is used. It is done.
[0023]
The solenoid temperature estimation device causes the control unit 4 to send a signal from an oil temperature sensor (oil temperature sensor) 51 that detects an oil temperature (for example, an oil temperature in an oil pan of an engine) as an environmental temperature, and each solenoid valve (linear solenoid). ) And a signal from a current sensor (current detection resistor) 52 that detects a current flowing through 30 is input, and the microcomputer shown in the flowchart of FIG.
[0024]
Below, it demonstrates according to the flowchart of FIG.
In step 1 (denoted as S1 in the figure, the same applies hereinafter), the oil temperature Toil is detected based on a signal from the oil temperature sensor. This portion corresponds to the environmental temperature detecting means together with the oil temperature sensor 51.
[0025]
In step 2, the solenoid current Isol is detected based on the signal from the current sensor. This portion corresponds to the solenoid current detection means together with the current sensor 52. In step 3, a heating value equivalent value ΔT is obtained from the detected solenoid current Isol with reference to a table in which a heating value equivalent value (heating temperature) ΔT for the solenoid current Isol is previously determined and stored. This portion corresponds to solenoid heat generation amount calculation means.
[0026]
In step 4, the oil temperature Toil is determined. That is, the oil temperature Toil is in a high temperature range above a predetermined value T2 (eg, 120 ° C.), the oil temperature Toil is in a low temperature range below a predetermined value T1 (eg, 40 ° C.), or the oil temperature Toil is within a predetermined range (T1 to T2). Judge whether it is in the middle temperature range. Of course, T1 <T2.
[0027]
In the case of the high temperature region, the process proceeds to step 5 to add the solenoid heat generation amount equivalent value ΔT to the oil temperature Toil to calculate the solenoid temperature Tsol = Toil + ΔT.
In the case of the low temperature range, the process proceeds to Step 6 to calculate a solenoid temperature Tsol = Toil−Tc by subtracting a predetermined value Tc from the oil temperature Toil. The predetermined value Tc may be a constant, but may be set according to the oil temperature Toil and may be increased as the oil temperature Toil is lower.
[0028]
Also in this case, the heat generation amount equivalent value ΔT may be taken into consideration, for example, the solenoid temperature Tsol = Toil− (TC−ΔT) may be calculated. Here, TC is a constant.
[0029]
If the temperature is in the middle temperature range, the process proceeds to step 7 where the oil temperature Toil is set to the solenoid temperature Tsol = Toil as it is.
Here, steps 4 to 7 correspond to solenoid temperature calculation means.
[0030]
As described above, by estimating the solenoid temperature from the environmental temperature (oil temperature) and the value corresponding to the amount of heat generated according to the current flowing through the solenoid, the solenoid temperature can be obtained accurately without adding a special sensor. It is done.
[0031]
Thereby, it becomes possible to correct | amend correctly the change of the solenoid characteristic (duty-drive current characteristic) by solenoid temperature, and an exact control is realizable.
[Brief description of the drawings]
FIG. 1 is a functional block diagram showing the configuration of the present invention. FIG. 2 is a system diagram of an automatic transmission for a vehicle. FIG. 3 is a hydraulic circuit diagram for each friction engagement element. Description】
1 Engine 2 Automatic transmission 3 Solenoid valve unit 4 Control unit 20 Friction engagement element 30 Solenoid valve (linear solenoid)
51 Oil temperature sensor 52 Current sensor

Claims (6)

Environmental temperature detecting means for detecting the environmental temperature;
Solenoid current detection means for detecting the current flowing through the solenoid;
Solenoid heat generation amount calculating means for calculating a value corresponding to the heat generation amount of the solenoid based on the current;
Solenoid temperature calculation means for calculating a solenoid temperature based on the environmental temperature and the calorific value equivalent value;
Is configured to include a,
The solenoid temperature calculation means calculates the solenoid temperature by adding the value corresponding to the heat generation amount to the environmental temperature in a high temperature range of the environmental temperature, and calculates a predetermined value Tc from the environmental temperature in the low temperature range of the environmental temperature. Is subtracted to calculate the solenoid temperature, and in the middle temperature range between the high temperature range and the low temperature range, the environmental temperature is used as it is as the solenoid temperature. 2. The solenoid temperature estimating apparatus according to claim 1, wherein the solenoid is used for hydraulic control, and the environmental temperature detecting means detects the temperature of the hydraulic oil. 2. The solenoid heat generation amount calculation means is configured to calculate a heat generation amount equivalent value by referring to a table in which a heat generation amount equivalent value for a solenoid current is previously determined and stored. 3. The solenoid temperature estimation device according to 2. The solenoid temperature estimation device according to any one of claims 1 to 3, wherein the predetermined value Tc is a constant. 4. The solenoid temperature estimation device according to claim 1, wherein the predetermined value Tc is set according to the environmental temperature, and is increased as the environmental temperature is lower. 5. The solenoid temperature estimation device according to any one of claims 1 to 3, wherein the predetermined value Tc is a value obtained by subtracting the calorific value equivalent value from a constant TC.

Images