JP4015451B2 - Control device for vehicle drive train - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for a drive train of a vehicle, comprising an engine and a transmission, for example, an automatic transmission, and having a drive train control device and a transmission control device arranged in the vicinity of or in the automatic transmission.
[0002]
[Prior art]
In recent years, a control device for a vehicle drive train is often installed inside an automatic transmission or outside a casing thereof. Transmission oil contained in the vehicle's automatic transmission may rise to around 140 ° C even in normal driving conditions of the vehicle, causing the vehicle's automatic transmission to be in severe operating conditions, such as frequent shifting operations. If it falls, it may get higher temperature due to heat from the transmission. On the other hand, the control device for controlling the operation of the automatic transmission includes a microcomputer element and a driving power transistor element, and in particular, the driving power transistor element in which heat generation from itself causes a problem performs a predetermined transistor operation. In order to guarantee this, it is necessary that the junction temperature does not become higher than the maximum allowable value. The same applies to semiconductor active elements such as IC elements and other transistor elements.
[0003]
[Problems to be solved by the invention]
However, in the conventional control device of this type, no measures are taken even though the temperature of the automatic transmission for the vehicle is operating at a high temperature close to the use limit of the semiconductor element as described above. Is the current situation. Therefore, when the temperature of the automatic transmission becomes higher than the normal value for some reason, the control device does not operate normally, the vehicle failure diagnosis device operates, and the subsequent control becomes impossible. ing.
[0004]
An object of the present invention is to propose a control device for a drive train of a vehicle that can solve the above-mentioned problems in the prior art.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, according to the invention of claim 1, control over the drive train of a vehicle disposed in the vicinity of or inside the automatic transmission for controlling the drive train of the vehicle including the internal combustion engine and the automatic transmission. A voltage detection means for detecting a voltage level of a supply voltage supplied to the control device, a storage element storing a conversion table of the voltage level of the supply voltage and a reference temperature value, and the voltage detection means A reference value determining means comprising means for determining a reference temperature value according to the voltage level with reference to the conversion table, and a temperature sensor for detecting the temperature inside the control device, in response to the temperature sensor groups temperature inside it is determined in the reference value determining means of the control device And a power supply stopping means for energizing the heating element in the control device stops when a temperature value above, the conversion table is, the voltage level of the supply voltage of the automatic transmission and the temperature sensor The reference value does not depend on the voltage level when the temperature gradient between the transmission oil and the transmission oil is smaller than a predetermined value, and the voltage level increases as the voltage level becomes higher than the range. A control device for a drive train of a vehicle is proposed, characterized in that the reference value is determined to be small.
[0006]
When the internal temperature in the control device becomes higher than a given reference value, energization to the heat generating element (for example, a driving transistor or an IC element) is stopped. As a result, the required control operation by the control device is stopped, and the automatic transmission is generally shifted to the fourth speed and fixed thereto. As a result, the speed change operation is not performed in the automatic transmission, the temperature of the automatic transmission decreases, and the internal heat of the control device disappears. Therefore, the internal temperature of the control device begins to gradually decrease, and the control device It can be prevented from being damaged. Then, the control device can be operated again.
[0008]
The temperature gradient between the heat generating element and the temperature sensor depends on the power consumption in the heat generating element, and this power consumption is related to the level of the supply voltage from the power source such as the on-vehicle battery to the control device. Therefore, by determining the reference value according to the voltage level, it is possible to stop energization of the heat generating element at a more appropriate timing.
[0009]
According to a second aspect of the present invention, in the first aspect of the present invention, the identification means for identifying the drive pattern of the drive circuit of the control device, and the reference value is determined based on the identification result of the identification means. And a control apparatus for a vehicle drive train with the following means.
[0010]
The drive circuit is one of the main heat generation elements in the control device, and the heat generation state changes depending on the drive signal applied to the drive circuit, particularly the pattern of the drive current signal. By identifying the drive pattern and determining the reference value according to the identification result, the energization of the heat generating element is more stopped at the timing in consideration of the actual temperature gradient between the heat generating element and the temperature sensor at that time. Performed at the appropriate time.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.
[0012]
FIG. 1 is a schematic overall view for explaining an example of an embodiment of the present invention of a control device for a drive train of a vehicle. FIG. 1 shows a drive train 10 for a vehicle in which an internal combustion engine 1 and an automatic transmission 2 are connected, and a control device 20 for controlling the automatic transmission 2 is incorporated in the automatic transmission 2. Note that the control device 20 does not necessarily have to be incorporated in the automatic transmission 2 and can be disposed outside or in the vicinity of the casing 2A of the automatic transmission 2.
[0013]
A position switch 2B is also provided inside the automatic transmission 2, and the position switch 2B detects which select position the select lever 2C is set to and a position signal S1 indicating the detection result is controlled by the control device. 20 to send.
[0014]
FIG. 2 shows a cross-sectional view of the control device 20. The control device 20 includes a casing 21 that constitutes a two-piece metal sealed oil-tight case composed of a bottom plate 21A and a cover case 21B. In the casing 21, a ceramic substrate 22 is an inner surface of the bottom plate 21A. 21Aa is fixed by adhesion or other appropriate means in close contact as shown in the figure. On the ceramic substrate 22, a microcomputer 23 and a driving IC element 24 to which a driving current signal according to a calculation result in the microcomputer 23 is given are incorporated. Various other parts constituting electronic components and circuit elements are assembled on the ceramic substrate 22, but these are not shown.
[0015]
A plurality of connection terminals T are fixed to the bottom plate 21A via sleeves S made of an electrically insulating material, and the ceramic substrate 22 and an external circuit can be connected via these connection terminals T. It has become.
[0016]
Each of the microcomputer 23 and the driving IC element 24 shown in FIG. 2 is a heating element that operates upon receiving power supply from an in-vehicle battery (not shown) as will be described later, and generates heat by an operating current flowing at this time. However, although the amount of heat generated in the microcomputer 23 is small, the amount of heat generated in the driving IC element 24 is considerably large, and the driving IC element 24 is the main heat generating element in the control device 20.
[0017]
A temperature sensor 25 for detecting the temperature inside the control device 20 is provided in the vicinity of the driving IC element 24. As the temperature sensor 25, for example, an appropriate temperature sensitive resistor, a temperature sensitive semiconductor element, or the like can be used. In the present embodiment, a temperature sensor 25 is provided in the vicinity of the driving IC element 24 in order to detect the temperature in the vicinity of the driving IC element 24 that is the main heat generating element having the highest temperature inside the control device 20. However, the arrangement position of the temperature sensor 25 is not limited to this, and can be set to an appropriate position according to the purpose of temperature detection.
[0018]
Since the casing 21 has an oil-tight structure, transmission oil in the automatic transmission 2 does not enter the control device 20 even if the control device 20 is disposed in the automatic transmission 2.
[0019]
FIG. 3 is a block diagram showing a schematic configuration of a circuit of the control device 20 shown in FIG. In FIG. 3, reference numeral 26 denotes a power supply circuit which receives a DC voltage VB from a vehicle battery (not shown) and supplies a stabilized DC voltage VC lower in voltage to the microcomputer 23. A DC voltage VB is applied to the driving IC element 24, and a solenoid of a solenoid valve for hydraulic control of a hydraulic circuit (not shown) for gear shift operation in response to a control output signal CS from the microcomputer 23. The required drive currents J1 and J2 are supplied to SV1 and SV2. In the present embodiment, the drive currents J1 and J2 are supplied by one of two different drive patterns. One is a driving pattern 1 having a large average driving current, and the other is a driving pattern 2 having a medium average driving current. Since the control operation for the gear shift of the automatic transmission 2 executed in the control device 20 is known per se, a detailed description of the basic configuration of the control device 20 and the gear shift control operation based on this is omitted.
[0020]
The temperature sensor 25 outputs a detection signal SK indicating the internal temperature Ta in the vicinity of the driving IC element 24, and the detection signal SK is input to the microcomputer 23. The microcomputer 23 monitors whether or not the internal temperature Ta of the control device 20 detected by the temperature sensor 25 is higher than a predetermined reference temperature Tr, and the internal temperature Ta> the reference temperature Tr. In such a case, the driving of the driving IC element 24 is stopped to stop the flow of current from the battery (not shown) to the driving IC element 24, thereby reducing the amount of heat generated from the driving IC element 24 to zero. And has a protective function to lower the temperature.
[0021]
FIG. 4 is a flowchart showing a protection control program for achieving this protection function by the microcomputer 23. The protection control program 30 will be described. First, in step 31, a reference temperature calculation process for determining the reference temperature Tr is executed. As can be seen from the above description, the reference temperature calculated here is determined so that the junction temperature Tj of the driving IC element 24 in the control device 20 is a predetermined allowable value when the control device 20 is operated and the shift control of the automatic transmission is continued. The temperature is higher than the temperature Tjo, and the driving IC element 24 is likely to be inoperable or destroyed.
[0022]
FIG. 5 is a detailed flowchart for explaining the calculation process for determining the reference temperature Tr in step 31. Here, in step 41, the reference temperature data DTr stored in advance in the ROM 23A (see FIG. 2) in the microcomputer 23 is read, and the value of the reference temperature Tr is determined according to the content of the reference temperature data DTr. Return to 31.
[0023]
Returning to FIG. 4, in the next step 32, the internal temperature Ta indicated by the detection signal SK input from the temperature sensor 25 to the microcomputer 23 is compared with the reference temperature Tr. If Ta ≦ Tr, the determination result of step 32 is NO, and the process proceeds to step 33, where the control device 20 performs the shift control of the automatic transmission 2 and returns to step 31.
[0024]
On the other hand, if Ta> Tr, the determination result in step 32 is YES, and the process proceeds to step 34 where the driving of the driving IC element 24 is stopped. As a result, no current flows through the driving IC element 24, which is the main heat source, and the temperature of the control device 20 itself does not increase. Further, in response to the control device 20 stopping the shift control, the automatic transmission 2 is gear-shifted to the fourth speed, and the gear is fixed thereto. That is, the shifting operation is not performed in the automatic transmission 2, and the state is fixed to the fourth speed. Therefore, no heat is generated due to the automatic transmission 2 performing a speed change operation. For these two reasons, the temperature of the automatic transmission 2 including the control device 20 gradually decreases thereafter.
[0025]
When the execution of step 34 ends, the process returns to step 31 and the above-described operation is repeated. Then, when the temperature of the control device 20 decreases with the passage of time and returns to the state of Ta ≦ Tr, step 33 is executed, and the shift control of the automatic transmission 2 by the control device 20 is started again.
[0026]
As described above, according to the control device 20, when the internal temperature Ta becomes higher than the reference temperature Tr, the shift control of the automatic transmission 2 is stopped, and the automatic transmission 2 is fixed to the fourth speed so that the control device 20 and The temperature of the automatic transmission 2 is lowered, and when Ta ≦ Tr is satisfied, the shift control of the automatic transmission 2 by the control device 20 can be started again.
[0027]
In the above embodiment, the value of the reference temperature Tr is a fixed value, but the value of the reference temperature Tr can be changed according to an appropriate parameter.
[0028]
FIG. 6 shows a configuration in which the value of the reference temperature Tr is set according to the value of the DC voltage VB from the battery. This configuration will be described. In step 51, the value of the DC voltage VB is read. In step 52, the voltage-temperature conversion table stored in the ROM 23A in the microcomputer 23 is referred to obtain the level of the DC voltage VB at that time. A corresponding reference temperature Tr is determined.
[0029]
FIG. 7 is a graph for explaining the voltage-temperature conversion table. Here, when the DC voltage VB is low, the value of the reference temperature Tr does not depend on the DC voltage VB. When the DC voltage VB becomes higher than a certain level, the value of the reference temperature Tr decreases as the DC voltage VB increases. It is a characteristic.
[0030]
The advantage of determining the value of the reference temperature Tr according to the characteristic shown in FIG. 7 by the value of the DC voltage VB is as follows. The temperature gradient between the heat generating element and the temperature sensor 25 depends on the power consumption in the heat generating element, but this power consumption is related to the level of the DC voltage VB that is the supply voltage from the power source such as the vehicle-mounted battery to the control device. is doing. Therefore, by determining the reference temperature Tr according to the level of the DC voltage VB, it is possible to stop energization of the heat generating element at a more appropriate timing.
[0031]
This will be described more specifically with reference to FIG. The temperature gradient among the driving IC element 24 (heating element), the temperature sensor 25, and the transmission oil depends on the power consumption in the driving IC element 24. Therefore, as shown by two characteristic lines in FIG. 8, when the DC voltage VB is low, the temperature gradient between them is small, but when the DC voltage VB is high, the power consumption in the driving IC element 24 is low. Increases, the temperature gradient between them becomes large.
[0032]
As a result, the temperature difference Tx between the temperature of the driving IC element 24 (heating element) when the DC voltage VB is low and the temperature of the temperature sensor 25 is small, and the driving IC element 24 (heating element) when the DC voltage VB is high. ) And the temperature of the temperature sensor 25 become larger. That is, the difference between the temperature detection value of the temperature sensor 25 and the actual heat generation temperature in the heat generating element changes according to the voltage level of the supply voltage.
[0033]
Therefore, according to the configuration in which the reference temperature Tr is determined according to the voltage level in response to the voltage detection unit that detects the voltage level of the DC voltage VB that is the supply voltage supplied to the control device 20, the temperature difference Tx and the temperature difference Ty It is possible to prevent the difference between the two from changing greatly regardless of the change in the voltage level of the DC voltage VB. Therefore, the temperature sensor 25 can always detect the temperature of the driving IC element 24 (heat generating element) with a constant temperature difference, so that the temperature sensor 25 can detect the temperature of the driving IC element 24 (heat generating element) accurately. Thus, it is possible to stop energization of the driving IC element 24 (heat generating element) at an appropriate timing.
[0034]
That is, even if the voltage level of the DC voltage VB changes, the temperature of the driving IC element 24 can be accurately detected by the temperature sensor 25, and the control operation of the control device 20 can be stopped at an appropriate timing. The energization is stopped even though the temperature of the IC element 24 for driving is not so high, or conversely, the energization is not stopped but the temperature of the driving IC element 24 is considerably high but the driving IC element 24 is burned. There will be no problems such as
[0035]
FIG. 9 shows a configuration example in which the value of the reference temperature Tr is set according to the drive pattern of the drive IC element 24.
[0036]
First, in step 61, the driving pattern of the driving IC element 24 is identified. This identification can be made by referring to the driving data of the driving IC element 24 in the microcomputer 23, but any other method may be used.
[0037]
In step 62, it is determined whether or not the identification result in step 61 is the drive pattern 1 (high current drive). If the identification result in step 61 is the drive pattern 1, the determination result in step 62 is YES, and the process proceeds to step 63, where the reference temperature data DTr that is a fixed value preset in the ROM 23A is stored. A correction value −ΔT1 for correcting in the decreasing direction is set. Thereafter, step 64 is entered, where DTr−ΔT1 is calculated, and the correction calculation of the reference temperature data DTr with the result as DTr is executed. As a result, when the driving IC element 24 is driven by the driving pattern 1, the value of the reference temperature Tr is lowered by −ΔT1.
[0038]
On the other hand, if the determination result in step 62 is NO, the process proceeds to step 65, where it is determined whether or not the identification result in step 61 is drive pattern 2 (medium current drive). If the identification result in step 61 is the drive pattern 2, the determination result in step 65 is YES, and the process proceeds to step 66 where the reference temperature data DTr, which is a fixed value preset in the ROM 23A, is increased. A correction value + ΔT2 for correcting in the direction is set. Thereafter, step 64 is entered, where calculation of DTr + ΔT2 is performed, and correction calculation of the reference temperature data DTr with the result as DTr is executed. As a result, when the driving IC element 24 is driven by the driving pattern 2, the value of the reference temperature Tr is increased by + ΔT2.
[0039]
If the determination result in step 65 is NO, the correction value is set to zero in step 67 and step 64 is entered. Therefore, in this case, the reference temperature data DTr is not corrected.
[0040]
According to this configuration, when the driving IC element 24 is not driven in either the driving pattern 1 or 2, the reference temperature data DTr is not corrected, and the predetermined reference temperature data DTr set in the ROM 23A is not executed. Is used to determine the reference temperature Tr.
[0041]
However, when the driving IC element 24 is driven with the driving pattern 1, the reference temperature Tr is corrected to be lower by −ΔT1 than this. As a result, when it is estimated that the amount of heat generation is large due to the large current drive, the value of the reference temperature Tr is corrected to be small, and there is a problem due to the large temperature gradient with the temperature sensor 25. It does not occur. This is the same as the correction operation described above for the case where the DC voltage VB is high.
[0042]
On the other hand, when the driving IC element 24 is driven with the driving pattern 2, the reference temperature Tr is corrected to be higher by + ΔT2. As a result, when it is estimated that the amount of generated heat is small due to the medium current drive, the value of the reference temperature Tr is corrected so as to be high, and there is a problem that the temperature gradient with the temperature sensor 25 becomes small. It does not occur. This is the same as the correction operation described above for the case where the DC voltage VB is low.
[0043]
As a result, even if the driving pattern of the driving IC element 24 is switched, an appropriate reference temperature Tr is always given. Therefore, the temperature of the driving IC element 24 can be accurately detected by the temperature sensor 25, and the control operation of the control device 20 can be controlled. Although the stop can be performed at an appropriate timing and the temperature of the driving IC element 24 is not so high, the energization is stopped, or conversely, the temperature of the driving IC element 24 is considerably high. There is no problem that the energization is not stopped and the driving IC element 24 is combusted.
[0044]
【The invention's effect】
According to the present invention, as described above, in a control device for a vehicle drive train disposed near or in the automatic transmission for controlling the drive train of the vehicle including the internal combustion engine and the automatic transmission, In response to a temperature sensor for detecting the internal temperature, when the internal temperature of the control device exceeds a given reference value, the power supply to the heat generating element in the control device is stopped, thereby changing the transmission of the automatic transmission. The operation is stopped to lower the temperature of the automatic transmission, the cause of heat generation in the control device is removed, the control device is prevented from being damaged by overheating, and the control device can be operated again after the temperature is lowered.
[0045]
In addition, since the temperature gradient between the heating element and the temperature sensor depends on the power consumption in the heating element, the difference between the temperature detection value in the temperature sensor and the actual heating temperature in the heating element is the voltage level of the supply voltage. Therefore, according to the configuration in which the reference value is determined according to the voltage level in response to the voltage detection means for detecting the voltage level of the supply voltage supplied to the control device, the difference is the change in the voltage level of the supply voltage. Therefore, it is possible to effectively suppress the change in accordance with the above, and to stop energization of the heat generating element at a more appropriate timing.
[0046]
Furthermore, the heat generation state changes depending on the drive signal applied to the drive circuit, particularly the drive current signal pattern. In this case, the difference between the temperature detection value of the temperature sensor and the actual heat generation temperature of the heat generation element is the supply voltage. According to the configuration in which the reference value is determined based on the identification result of the identification means for identifying the drive pattern of the drive circuit of the control device, the difference is changed according to the voltage level. Therefore, it is possible to effectively suppress the change in accordance with the change of the power supply, and to stop energization of the heat generating element at a more appropriate timing.
[Brief description of the drawings]
FIG. 1 is a schematic overall view of a vehicle drive train for explaining an example of an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the control device shown in FIG.
3 is a block diagram showing a schematic configuration of a circuit of the control device shown in FIG. 2;
4 is a flowchart showing a protection control program executed in the microcomputer shown in FIG. 3;
FIG. 5 is a detailed flowchart of a reference temperature determination step in FIG. 4;
6 is a detailed flowchart showing another example of the reference temperature determination step in FIG. 4;
7 is a graph for explaining a voltage-temperature conversion table used in the process of FIG. 6;
FIG. 8 is a diagram for explaining advantages of the configuration shown in FIG. 6;
FIG. 9 is a flowchart for explaining a configuration when a reference temperature value is set according to a driving pattern of a driving IC element.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Automatic transmission 2B Position switch 2C Select lever 10 Drive train 20 Control apparatus 23 Microcomputer 24 Driving IC element 25 Temperature sensor 26 Power supply circuit CS Control output signal J1, J2 Drive current S Sleeve S1 Position signal SK Detection signal SV1 , SV2 Solenoid T Connection terminal VB DC voltage VC Stabilized DC voltage

Claims (2)

A control device for a vehicle drive train disposed near or in the automatic transmission for controlling a vehicle drive train including an internal combustion engine and an automatic transmission,
Voltage detection means for detecting a voltage level of a supply voltage supplied to the control device, a storage element storing a conversion table of the voltage level of the supply voltage and a reference temperature value, and the conversion in response to the voltage detection means Means for determining a reference temperature value according to the voltage level with reference to a table;
A temperature sensor for detecting the temperature inside the control device;
Energization stopping means for stopping energization of the heat generating element in the control device when the temperature inside the control device is equal to or higher than the reference temperature value determined in the reference value determining means in response to the temperature sensor And when the voltage level of the supply voltage is in a range where the temperature gradient between the temperature sensor and the transmission oil of the automatic transmission is smaller than a predetermined value, the reference value is A control apparatus for a drive train of a vehicle, characterized in that the reference value becomes smaller as the voltage level becomes higher as the voltage level becomes higher than the range without depending on the voltage level.   The vehicle drive train according to claim 1, further comprising: an identification unit for identifying a drive pattern of the drive circuit of the control device; and a unit for determining the reference value based on an identification result of the identification unit. Control device.

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