JP2004125028A - Cooling method and system for electronic control device for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a proper cooling method and system capable of solving a problem of need for cooling in a case where an electronic control device for shifting is provided in a housing of an automatic transmission, which has a deterioration/damage due to heat generation in semiconductors in the electronic control device caused by heat generation of transmission oil. <P>SOLUTION: Oil temperature in the automatic transmission or electric part temperature in the electronic control device is detected, and a detected temperature is compared with a predetermined temperature. When the detected temperature is higher than the predetermined temperature, oil temperature inside a case of the automatic transmission is lowered by putting an electric fan on, forcedly connecting a lockup clutch, reducing pressure control value of a pressure regulator, or generating a gear shift ratio reducing warning or the like. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electronic control unit for a vehicle, and more particularly, to a method and a system for cooling an electronic control unit mounted in an automatic transmission.
[0002]
[Prior art]
[Patent Document 1] Japanese Patent Application Publication No. Hei 8-510317 Conventionally, an electronic control unit (hereinafter referred to as a control unit) for an engine or an automatic transmission has been installed in a vehicle interior. It has been required to be installed outdoors. Further, if the electronic control device and the control target are far apart, wiring routing becomes complicated, and wiring laying cost is increased. Therefore, there is a demand to provide an electronic control device near a control target. Therefore, there is an increasing demand for integration of the electronic control device and its control target, that is, so-called modularization. In other words, the electronic control unit for the engine should be installed in the engine room, preferably in the engine itself, and the control unit for the automatic transmission should also have the technology to realize the need for direct mounting on the automatic transmission or installation inside the automatic transmission. It has become.
[0003]
Specifically, as in the above-mentioned patent document, there is an example in which an electronic control device of an automatic transmission is disposed in a housing of the automatic transmission, and the electronic control device is cooled with oil for the automatic transmission. The conductive wire is formed as a steel wire, and one end of the wire is fixed to an electrical connection terminal of the control electronic circuit device, and the other end is fixed to the control means. The control electronics for controlling the transmission are located inside the transmission casing. As a result, the space existing in the transmission casing can be fully utilized, and the length of the conductive wire can be shortened, thereby saving the conductive wire.
[0004]
[Problems to be solved by the invention]
However, in such a case, since the heat generated by the automatic transmission is affected, it is important to improve the cooling efficiency. The patent document proposes that this heat radiation be performed by oil in the automatic transmission. However, the temperature of the oil in the automatic transmission increases due to heat generated by slippage during torque transmission by the torque converter and the clutch. In particular, if the hill-climbing or towing travel is continued for a long time, the temperature may rise to 130 to 140 ° C. even when cooled by an oil cooler, and it can hardly be used for cooling (radiation) of the electronic control device. The control device will get the heat.
[0005]
On the other hand, silicon semiconductors, including CPUs, are designed to have a maximum junction temperature (Tjmax) of 150 ° C., so if self-heating is added, it is possible that the temperature will exceed 150 ° C. In addition, there is a possibility that the electronic control device becomes uncontrollable due to failure or deterioration of the semiconductor. Also, the guaranteed temperature of the oil of the automatic transmission is usually about 130 ° C. If the temperature becomes higher due to self-heating of the electronic control unit, the components in the oil are decomposed, and the torque transmission efficiency expected at the beginning And there is also a problem that the clutch plate is damaged.
[0006]
An object of the present invention is to provide a cooling method for maintaining the function of an electronic control device by effectively using a cooling system for a vehicle or an automatic transmission as needed in order to solve the above problems.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, means for detecting the oil temperature in the automatic transmission case or preferably the temperature of the semiconductor in the electronic control device is provided, and the electronic control device provided in the automatic transmission according to the temperature or the temperature gradient. This is a configuration for performing cooling.
[0008]
Detecting an oil temperature in the automatic transmission or a temperature or a temperature gradient of an electronic component in the electronic control device, and comparing the detected temperature with a predetermined temperature or the detected temperature gradient and a predetermined temperature gradient. And cooling the oil in the automatic transmission case when the detected temperature or the temperature gradient exceeds the predetermined temperature or the temperature gradient.
[0009]
Cooling of the oil in the automatic transmission case is performed by starting a radiator fan for cooling an oil cooler to cool the oil in the case. Further, when the detected temperature exceeds the predetermined temperature or when the detected temperature gradient exceeds the predetermined temperature gradient, engaging the lock-up clutch of the automatic transmission, Alternatively, the set hydraulic pressure value of the pressure regulator provided in the automatic transmission is changed to a lower set value side or a lower limit value, and when the detected temperature exceeds the predetermined temperature or the detection is performed. When the detected temperature gradient exceeds the predetermined temperature gradient, a warning that prompts a change in gear ratio is issued, and the electric motor is driven in accordance with the detected temperature or the temperature gradient by using an electric motor driven oil pump. To control the rotation speed of the motor.
[0010]
Also, an electronic component temperature in the electronic control device or an oil temperature detecting device in the device, and when the detected temperature exceeds a predetermined temperature or when the detected temperature gradient is a predetermined temperature gradient, And cooling means for cooling the oil in the automatic transmission case when it exceeds.
[0011]
Further, the cooling means has a radiator fan for cooling an oil cooler, a lock-up clutch fastening means, a setting change means of a set pressure of a pressure regulator in a lower limit direction, or a warning means for urging a downshift. Further, the cooling means has an electric motor drive oil pump, and controls the rotation speed of the electric motor according to a temperature or a temperature gradient detected by an electronic component temperature in the electronic control device or an oil temperature detection device in the device. The cooling system of the electronic control unit for an automatic transmission is provided with means for controlling the change.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an electronic control unit for an automatic transmission showing an example of an embodiment of the present invention, and FIGS. 2, 3, and 4 are flowcharts of executing a cooling cycle by the electronic control unit. FIG. 5 is a vehicle system diagram including the electronic control device.
[0013]
In FIG. 1, an automatic transmission electronic control unit 2, sensors and switches, and solenoid valves are mounted in an automatic transmission case 1. Further, from the automatic transmission case 1 to the outside, only a battery power line 10 and a CAN communication bus 11 linked to an IGN key not described are connected, and most automatic transmission control systems are provided with the automatic transmission. It is stored in the machine case 1.
[0014]
The battery power supply line 10 is connected to the electronic control unit 2 for the transmission, and a battery voltage is supplied. Then, at the same time when a voltage is supplied to the CPU 3 via the constant voltage means 4, a clock signal is generated by the oscillator 7, and various controls are executed according to a built-in program. The rotation sensor signal 12, the range select signal 13, and the signal of the oil temperature sensor 14 composed of a thermistor are taken into the input stage circuit 5, and after being processed by the CPU 3, the output signal is output via the output stage circuit 6 to the shift solenoid ( SOL.A) 16, the shift solenoid (SOL.B) 17, the line pressure solenoid (SOL.C) 18, and the lock-up solenoid (SOL.D) 19 to control and maintain the automatic transmission in an optimal state. ing.
[0015]
Note that an engine rotation signal, a throttle opening signal, and the like required for transmission control are taken in from the outside via the CAN communication bus 11 and the CAN communication drive stage 9 and transmitted to the outside. Further, another electronic component temperature sensor 15 mounted on the board for detecting the internal temperature of the electronic control device 2 is also taken into the CPU 3 in the same manner as other input signals. Reference numeral 22 denotes an engine electronic control unit.
[0016]
Next, a specific cooling cycle execution flow of the transmission electronic control unit 2 will be described with reference to FIG. First, in the flow chart of the cooling control, the electronic control unit 2 periodically (for example, every 100 ms) measures the substrate temperature T _ICT by the oil temperature sensor 14 or the electronic component temperature sensor 15 in step 1. In step 2, an estimated temperature T _IC after a certain time (for example, after 10 seconds or 30 seconds) is calculated from the measured value T _ICT by, for example, a method such as extrapolation. In step 3, the CPU 3 compares a predetermined allowable temperature T _HI (for example, 140 ° C.) of the circuit board with the estimated value T _{IC in the} CPU 3.
[0017]
As a result, if T _IC ≧ T _HI , the process _{proceeds to} step 4 to start a cooling cycle to cool the electronic control unit 2 (detailed flow is shown in FIG. 3). If it is determined in step 3 that T _IC <T _HI after the execution of the cooling cycle, in step 5, the set temperature T _LO lower than T _IC and T _HI (T _LO <T _HI , for example, 100 ° C.) is set. The comparison is performed in the CPU 3, and as a result, if it is determined that T _IC ≦ T _LO , the cooling cycle is ended in step 6. Here, the difference between T _HI and T _LO is provided as a hysteresis, and is set to a realistic value that does not cause hunting.
[0018]
In FIG. 2, the determination is performed using the estimated temperature T _IC after a predetermined time calculated based on the substrate temperature T _ICT , but depending on the temperature gradient change, the circuit board allowable temperature T _HI may be determined. It is assumed that overshoot will occur only by comparison with. In this case, although not shown, a magnitude judgment of the temperature gradient as shown in the following equation (1) may be incorporated in place of the judgment logic of step 3.
[0019]
T _GRAD ≧ K (1)
However,
T _GRAD (n) = {T _ICT (n) -T _ICT (n-5)} / 500 ms
K = permissible temperature gradient The temperature gradient with which data should be set may be set and selected in advance, and the same applies to the permissible temperature gradient. Often set based on empirical data.
[0020]
Next, a specific cooling cycle of step 4 will be described with reference to FIG. In step 41, first, cooling is started by forcibly turning on the electric fan (see FIG. 4). Thereafter, the necessity of the cooling means to be subsequently performed is determined by comparing the values with the values higher than the temperature T _HI , for example, T _HI1 = 130 ° C. and T _HI2 = 140 ° C.
[0021]
If T _IC ≧ T _HI1 as a result of comparison with T _HI1 in step 42, it is _checked in step 43 whether the lock-up clutch can be forcibly engaged. If the vehicle is not accelerating or shifting, the lock-up is possible and the lock-up clutch is forcibly engaged in step 44. However, if lock-up is not possible, that is, if the vehicle is accelerating or shifting, the lock-up clutch is released at step 45 instead of forcibly engaging the lock-up clutch. In step 46, it is checked whether or not the pressure adjustment value of the pressure regulator is at the required lower limit of hydraulic pressure calculated from the operating condition. If it is not the lower limit, the pressure regulating value of the pressure regulator is further changed to the lower limit or to the lower limit in step 47 in order to increase the surplus oil amount.
[0022]
If T _IC ≧ T _HI2 in step 48, the process shifts to step 49 to shift to the process of increasing the pump discharge pressure by downshifting. However, downshifting in an unintended state by the driver impairs drivability, such as sudden engine braking.At this stage, a warning to prompt downshift is displayed on the instrument panel, etc., and the driver is prompted to downshift. Generate an alarm.
[0023]
Next, a specific end of the cooling cycle in step 6 shown in FIG. 2 will be described with reference to FIG. That is, according to each cooling means in step 4, the electric fan is turned off in steps 61 to 64, the lock-up is released, the pressure regulation value of the pressure regulator is returned to the original value, and the warning for downshifting is released. Become.
[0024]
There are the cooling methods as described above, and the following four methods are summarized below. In the first method, a signal for forcibly engaging the vehicle is output from the vehicle control device to the lock-up clutch of the torque converter in the automatic transmission. The torque converter performs torque amplification and transmission by a rotation difference between the pump impeller and the turbine liner, but the rotation difference becomes a slip and becomes a large heat source. Originally, there was a function to reduce the rotation difference to zero by engaging the lock-up clutch in a region other than the region where torque amplification is necessary, such as when starting, but the lock-up clutch was often opened even during running, with emphasis on riding comfort. Therefore, at a high temperature, the lock-up clutch is forcibly engaged within a range that does not impair the operability with respect to the normal control.
[0025]
The second method is configured to send a forced ON instruction from the electronic control device in the automatic transmission to the control device of the radiator electric fan via the in-vehicle network bus. Normally, the oil of the automatic transmission is temporarily cooled by an oil cooler built in or near the radiator and returned to the automatic transmission again. However, if the heat generated in the automatic transmission is large, the cooling efficiency of the oil cooler must be increased accordingly.However, electric fans for radiators are generally controlled only to keep the water temperature constant. Did not. Therefore, cooling to oil was of low priority. Therefore, the oil temperature returned to the automatic transmission is cooled by forcibly turning on the radiator electric fan within a range that does not impair the fuel efficiency and power performance of the engine.
[0026]
A third method is to provide a means for reducing the pressure adjustment value of the pressure regulator. After the oil cooled by the oil cooler is pressurized by an oil pump, the pressure is regulated to a constant pressure by the pressure regulator, and the surplus oil is used for cooling the electronic control unit. Since the value is set to a necessary and sufficient value in the entire operation range, the setting is considerably higher than the required minimum oil pressure calculated from the operation state. Therefore, by limiting the hydraulic pressure to the minimum for each operating condition, it is possible to further reduce the pressure regulation value, increase the surplus oil amount, and increase the cooling efficiency.
[0027]
A fourth method is configured to issue a command to lower the gear ratio from the electronic control unit. The oil pump is directly connected to the engine rotation shaft.At the same vehicle speed, the lower the gear ratio, the higher the engine speed and the higher the pump discharge pressure, resulting in an increase in the amount of surplus oil cooled. Cooling efficiency can be increased. However, this method is limited to displaying an alarm or generating an alarm. By using at least one of these four processes, it is possible to prevent the deterioration and damage of the semiconductor in the electronic control device or the deterioration of the oil. Further, the oil pump may not be directly connected to the engine but may be driven by the electric pump 40, and the control device 50 may control the rotation speed of the electric pump according to the detected temperature. In the case of this control method, there is an effect that the discharge pressure can be more finely controlled.
[0028]
Next, the first cooling means will be described with reference to the vehicle system diagram of FIG. The engine 21 is controlled by an engine electronic control unit 22, and a water-cooled radiator 23 is mounted to cool engine oil (not shown) in the engine 21. An electric fan 24 for air cooling is provided for cooling the water-cooled radiator 23. The electric fan 24 is controlled by the engine electronic control unit 22 based on a water temperature detected via a water temperature sensor signal 25. Have been. The radiator 23 has an oil cooler 20 built therein. The oil enters the oil cooler via a cool line pipe 26 and returns to the automatic transmission case 1 via a cooler out pipe 27. I have.
[0029]
First, when the electronic control unit 2 determines that cooling is necessary (step 3 in FIG. 2), an instruction to turn on the electric fan 24 is transmitted to the engine electronic control unit 22 via the CAN communication bus 11. . Based on the instruction, the engine electronic control unit 22 controls the on / off control of the radiator fan so that the water temperature becomes, for example, around 100 ° C. However, from the viewpoint of the performance of the engine, it is considered that there is no problem even if the temperature is about 85 ° C. to 115 ° C.), and the electric fan 24 is started to increase the cooling efficiency of the oil cooler 20.
[0030]
Next, the second cooling means will be described based on the automatic transmission system configuration diagram of FIG. The oil cooled by the oil cooler 20 in the radiator 23 is sucked up by an oil pump 29 from an oil pan 28, and then regulated to a constant pressure by a pressure regulator (valve) 30 to control valves for shifting and lock-up. A hydraulic pressure 31 and a torque transmitting hydraulic pressure 32 are generated. However, the oil pump 29 is directly connected to the engine 21, and the discharge pressure also changes according to the engine speed.
[0031]
Here, (discharge pressure)-(constant pressure regulation) becomes surplus oil and is returned to the oil pan 28 as a drain. The pressure regulation value of the pressure regulator (valve) 30 is controlled by the line pressure solenoid 18 so as to be an optimal oil pressure for an operation condition, and mechanically fixes the pump impeller 35 and the turbine liner 36 in the torque converter 34. The lock-up clutch 37 is controlled by a signal from the lock-up solenoid 19.
[0032]
Further, the electronic control unit 2 estimates an operation state from an engine rotation signal and a throttle opening signal taken from the CAN communication bus 11, the rotation sensor signal 12, and the range signal 13, and controls the shift solenoids 16 and 17. The gear ratio of the automatic transmission is reduced to a limit that does not impair drivability by a combination of ON / OFF. However, this is only a warning display and is actually performed by the driver (fourth means).
[0033]
As a result, the engine speed is increased, the pump discharge pressure is increased, and the excess cooled oil can be used for oil cooling of the transmission electronic control unit 2, thereby increasing the cooling effect. Similarly, by using the line pressure solenoid 18 which sets the pressure adjustment value of the pressure regulator (valve) 30 and lowering the pressure adjustment value to the minimum pressure at which the clutch engagement force can be secured, excess cooled oil is reduced. Since it can be used for oil cooling of the transmission electronic control unit 2, the cooling effect is improved. This is the third means.
[0034]
At the same time, when the lock-up solenoid 19 is not turned on, the lock-up clutch 37 is engaged via the lock-up valve 33 by forcibly turning it on. As a result, the slip in the torque converter 34 is eliminated, and the heat generated by the oil itself is reduced, so that the heat (received heat) from the oil to the electronic control unit 2 for the transmission is reduced.
[0035]
Another embodiment will be described with reference to FIG. The difference from FIG. 6 is that the oil pump 38 is driven by a motor. Although the cooling principle is not described because it overlaps with FIG. 6, in the future hybrid vehicles and the like, hydraulic pressure is required even when the engine is stopped, so that the method driven by the motor becomes the mainstream. The setting can be made finely by the motor, and the surplus oil for cooling can be set freely.
[0036]
ADVANTAGE OF THE INVENTION According to this invention, even if the electronic control unit built in the automatic transmission is exposed to a high temperature environment due to abnormal heat generation of the oil, the oil temperature can be reduced by effectively using the existing cooling means (cooling function). Therefore, it is possible to provide a configuration for preventing the semiconductor in the electronic control device from being damaged. Further, by cooling the oil temperature, it is possible to prevent the torque transmission characteristics required for the automatic transmission from deteriorating.
[0037]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, even if the electronic control unit built in the automatic transmission is exposed to a high temperature environment due to abnormal heat generation of the oil, the oil temperature can be reduced, and as a result, damage to the semiconductor in the electronic control unit can be reduced. Can be provided. Further, by cooling the oil temperature, it is possible to prevent the torque transmission characteristics required for the automatic transmission from deteriorating.
[Brief description of the drawings]
FIG. 1 is a block diagram of a first embodiment showing an electronic control unit for an automatic transmission.
FIG. 2 is a flowchart of a first embodiment showing execution of a cooling cycle.
FIG. 3 is a flowchart of a specific cooling execution cycle of the first embodiment.
FIG. 4 is a flowchart of a specific cooling end cycle of the first embodiment.
FIG. 5 is a system configuration diagram of a first embodiment showing a vehicle system.
FIG. 6 is a system configuration diagram of an embodiment showing an automatic transmission system.
FIG. 7 is a system configuration diagram of another embodiment showing an automatic transmission system.
[Explanation of symbols]
1; automatic transmission case 2; electronic control unit for automatic transmission 3; CPU 4; constant-current means 5; input stage circuit 6; output stage circuit 7; oscillator 9; CAN communication drive stage 10; CAN communication bus 12; rotation sensor signal 13; range select signal 14; oil temperature sensor 15; electronic component temperature sensor 16; shift solenoid A 17; shift solenoid B 18; line pressure solenoid 19; lock-up solenoid 20; Engine 22; engine electronic control unit 23; radiator 24; electric fan 25; water temperature sensor signal 26; cool line pipe 27; cooler out pipe 28; oil pan 29; oil pump 30; pressure regulator (valve) 31; Hydraulic pressure 32; torque transmitting hydraulic pressure 33; Click-up valve 34; the torque converter 35; pump impeller 36; the turbine liner 37; lock-up clutch 38; a motor-driven oil pump 40; motor 50; oil pump control device.

Claims (8)

In a method for cooling an electronic control unit for an automatic transmission disposed inside an automatic transmission case, the oil temperature in the automatic transmission or the temperature of electronic components in the electronic control unit is detected, and the detected temperature is determined in advance. Comparing the detected temperature or the detected temperature gradient with a predetermined temperature gradient, and when the detected temperature or the detected temperature gradient exceeds the predetermined temperature or the temperature gradient, A method for cooling an electronic control unit for an automatic transmission, comprising cooling oil in a transmission case. 2. The electronic device for an automatic transmission according to claim 1, wherein cooling of the oil in the automatic transmission case starts a radiator fan for cooling an oil cooler to cool the oil in the case. Control device cooling method. 2. The lock-up clutch of the automatic transmission according to claim 1, wherein the detected temperature exceeds the predetermined temperature or the detected temperature gradient exceeds the predetermined temperature gradient. A method of cooling an electronic control unit for an automatic transmission, wherein the electronic control unit is engaged, or a set hydraulic pressure value of a pressure regulator provided in the automatic transmission is changed to a lower set value side or a lower limit value. 2. The warning according to claim 1, wherein when the detected temperature exceeds the predetermined temperature or when the detected temperature gradient exceeds the predetermined temperature gradient, a warning prompting to change the gear ratio is issued. A method for cooling an electronic control unit for an automatic transmission, the method comprising: 2. The method for cooling an electronic control unit for an automatic transmission according to claim 1, wherein an oil pump driven by the electric motor is used, and the rotational speed of the electric motor is controlled to be changed according to the detected temperature or temperature gradient. In a cooling system of an electronic control unit for an automatic transmission disposed inside an automatic transmission case, a temperature of an electronic component in the electronic control unit or an oil temperature in the device, and the detected temperature are predetermined. Cooling means for cooling oil in the automatic transmission case when the temperature exceeds the temperature or when the detected temperature gradient exceeds a predetermined temperature gradient, for an automatic transmission. Electronic control unit cooling system. 7. The cooling unit according to claim 6, wherein the cooling unit is a radiator fan for cooling an oil cooler, a lock-up clutch engaging unit, a setting change unit of a pressure regulator set in a lower limit direction, or a warning unit for urging a downshift. A cooling system for an electronic control unit for an automatic transmission, comprising: 7. The electric motor according to claim 6, wherein the cooling means has an electric motor drive oil pump, and the electric motor rotates according to a temperature or a temperature gradient detected by an electronic component temperature in the electronic control device or an oil temperature detection device in the device. A cooling system for an electronic control unit for an automatic transmission, comprising: means for changing and controlling a speed.

Images