KR20110099641A - Estimating device and method for oil temparature - Google Patents

Abstract

An object of the present invention is to provide an oil temperature estimating apparatus and an oil temperature estimating method for estimating an oil temperature of working oil used in a vehicle.
An oil temperature sensor for outputting an output value corresponding to the oil temperature of the operating oil used for the vehicle, filter processing means for performing a first filter process for delaying the variation of the output value in a predetermined response, an output value in comparison with a predetermined threshold If the oil temperature corresponding to is equal to or greater than a predetermined threshold, filter switching means for switching the processing performed by the filter processing means to the second filter processing whose response is delayed rather than the first filter processing, and the first or second filter processing is performed. Based on the output value, oil temperature estimation means for estimating the oil temperature of the working oil is provided.

Description

Estimation apparatus of oil temperature and estimation method of oil temperature {ESTIMATING DEVICE AND METHOD FOR OIL TEMPARATURE}

The present invention relates to an oil temperature estimating apparatus and an oil temperature estimating method for estimating an oil temperature of working oil used in a vehicle.

Working fluids used in vehicles, such as engine oils, automatic fluids (ATFs) in automatic transmissions, power steering fluids used in power steering devices, brake fluids used in brake devices, etc. Viscous resistance) changes, so that hydraulic pressure and flow rate are controlled based on the oil temperature measured by the oil temperature sensor.

Since the oil temperature sensor mounted on the vehicle is affected by various noises, the control device that performs the control performs a filter process on the output value of the oil temperature sensor that measures the oil temperature in order to prevent the influence of the noise, The oil temperature is estimated based on the output value.

In this way, by using a filter for estimating the oil temperature, the first delay filter process is performed on the detection signal of the element temperature sensor that detects the temperature, and the oil temperature is calculated based on the value after the filter process. The power steering apparatus to be used is known (refer patent document 1).

Japanese Patent Application Laid-Open No. 2005-7951

According to the above-mentioned prior art, the filter process is performed on the oil temperature to delay the response to the fluctuation of the oil temperature, thereby preventing the influence of noise and the like.

By the way, it is known that oil temperature differs with an increase rate with the temperature. Since heat generated from a heat source of a vehicle such as an engine is constant to some extent, for example, the temperature of the ATF used in the automatic transmission is low at the beginning of the vehicle running in a cold district, but is heated by a heat source due to the running of the vehicle. And gradually converges to a certain temperature.

At this time, since the temperature difference with a heat source is large at the time of low temperature at the time of the vehicle running start, the rate of increase of oil temperature becomes large. On the other hand, after the oil temperature rises to some extent, the difference between the heat source and the oil temperature of the vehicle becomes small, so that the rate of increase of the oil temperature becomes small.

Therefore, when a filter designed for the purpose of removing noise of the oil temperature sensor at high temperature is applied at low oil temperature, it is not possible to follow the fluctuation of oil temperature, and the deviation from the actual oil temperature becomes large. there is a problem. On the other hand, when a filter designed to increase the followability of oil temperature fluctuations at low oil temperature is applied at high temperature, there is a problem that the noise becomes weak.

The present invention has been made in view of the above problems, and by performing appropriate filter treatment at low oil temperature and high oil temperature, the difference between estimated oil temperature and real oil temperature can be reduced and the influence of noise can be prevented. It is an object to provide a device for estimating oil temperature.

According to one embodiment of the present invention, a filter process for performing an oil temperature sensor for outputting an output value corresponding to an oil temperature of operating oil used in a vehicle, and a first filter process for delaying the variation of the output value in a predetermined response with respect to the output value. Means and the filter switching means for switching the processing performed by the filter processing means to the second filter processing whose response is delayed from the first filter processing when the oil temperature corresponding to the output value is equal to or greater than the predetermined threshold value; An oil temperature estimating means for estimating an oil temperature of operating oil is provided based on the output value in which 2 filter processing was performed.

According to the present invention, when the oil temperature corresponding to the output value of the oil temperature sensor is greater than or equal to a predetermined threshold, the filter process is performed so that the response is delayed more. Therefore, the oil temperature of the hydraulic oil used in the vehicle varies according to the temperature. When the oil temperature is high, the effect of noise can be prevented by delaying the response, and when the oil temperature is low, the delay of the response can be reduced to reduce the deviation from the actual oil temperature.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows the structure of the drive device of the vehicle of embodiment of this invention.
2 is a flowchart of the control of the transmission controller of the embodiment of the present invention.
3 is an explanatory diagram showing hysteresis of an oil temperature estimation process of an embodiment of the present invention.

EMBODIMENT OF THE INVENTION Below, the oil temperature estimation apparatus of embodiment of this invention is demonstrated with reference to drawings.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows the structure of the drive device of the vehicle of embodiment of this invention.

The drive device of the vehicle according to the embodiment of the present invention mainly controls the engine 10 as a drive source, an automatic transmission 20 that shifts and outputs a driving force of the engine 10, and controls the operation of the automatic transmission 20. It consists of a transmission controller (ATCU) (30).

The engine 10 rotates and drives the crankshaft 11 which is a rotating shaft by exploding fuel mixing intake. Torque converter 12 is connected to crankshaft 11.

The torque converter 12 is composed of a pump 121, a turbine 122, a stator 123, a lockup clutch 124, and the like.

When the pump 121 connected to the crankshaft 11 rotates, the drive force torque-amplified by the stator 123 is transmitted to the turbine 122 through hydraulic oil. The turbine 122 is connected to the main shaft 13, and transmits a driving force to the automatic transmission 20 by rotating the main shaft 13.

The lockup clutch 124 increases the transmission efficiency of the driving force by directly connecting the crankshaft 11 side which is an input side and the main shaft 13 of the output side.

The automatic transmission 20 includes a transmission mechanism 201 composed of a planetary gear mechanism, a belt type continuously variable transmission mechanism, a clutch, and the like, and the transmission ratio is changed by engaging or releasing the clutch or changing the diameter of the belt. The driving force is transmitted to the output shaft 14. Hydraulic oil (automatic transmission fluid, hereinafter referred to as "ATF") is used for the operation of the transmission mechanism 201 and the torque converter 12.

The final gear 21 is connected to the output shaft 14. The final gear 21 is provided with a differential device 211 to reduce the driving force output from the automatic transmission 20 and transmit it to the left axle 22 and the right axle 23 while allowing left and right differentials. The left axle 22 and the right axle 23 are provided with wheels 24 and 25, respectively.

The transmission controller 30 which controls the operation of the automatic transmission 20 determines the transmission ratio of the automatic transmission 20 based on input signals from various sensors and switches, and controls the transmission mechanism 201 based on this determination. do.

In addition, the transmission controller 30 controls fastening (including slip fastening) and release of the lockup clutch 124 of the torque converter 12 based on these input signals.

The transmission controller 30 includes a throttle valve opening sensor 31A, a brake switch 32A, an inhibitor switch 33A, a vehicle speed sensor 34A, an ATF oil temperature sensor 35A, an engine water temperature sensor 36A, and the like. The signal is input.

The throttle valve opening degree sensor 31A is provided in the throttle valve 31 of the engine 10 and detects the opening degree of the throttle valve. The brake switch 32A is provided in the brake pedal 32 to detect the operation of the brake pedal by the driver. The inhibitor switch 33A is provided in the shift lever 33 to detect the operation of the shift lever by the driver.

The vehicle speed sensor 34A is provided on the axle 22 or 23 to detect the traveling speed of the vehicle. The ATF oil temperature sensor 35A is provided in the automatic transmission 20 to detect the oil temperature of the ATF inside the automatic transmission 20. The engine water temperature sensor 36A detects the water temperature of the engine 10.

The transmission controller 30 performs lockup control of the torque converter based on input signals from these various sensors and switches. In this lockup control, the transmission controller 30 instructs the fastening hydraulic pressure to the actuator for fastening the lockup clutch 124. When the actuator is supplied with hydraulic pressure based on the indicated fastening hydraulic pressure, the lockup clutch 124 is fastened or released at a desired fastening pressure.

AFT, which is hydraulic oil, has a characteristic of low viscosity when the temperature is high and high viscosity when the temperature is low. Therefore, depending on the oil temperature of ATF, the behavior of an actuator changes even with the same indicated hydraulic pressure. To prevent this, the indicated hydraulic pressure is changed based on the oil temperature of the ATF.

The oil temperature of the ATF is measured by the ATF oil temperature sensor 35A. The ATF oil temperature sensor 35A converts the oil temperature into a voltage value and outputs it to the transmission controller 30. Since this output value includes noise in the sensor itself or during transmission, the transmission controller 30 performs a filter process so that a response may be delayed in response to the change of an output value in order to remove the influence by this noise. For example, the response is delayed by the weighted average of the output value of the previous ATF oil temperature sensor 35A and the output value of the current ATF oil temperature sensor 35A.

The transmission controller 30 converts the output value of the filtered ATF oil temperature sensor 35A to the ATF oil temperature by referring to the correspondence table between the predetermined output value and the ATF oil temperature. Based on this ATF oil temperature, lockup control is performed. For example, when the ATF oil temperature is low, the viscosity of the ATF is high, so that the required tightening pressure can be secured by correcting the indicated hydraulic pressure to the actuator of the lock-up clutch 124 to the large side. In addition, the output value of the ATF oil temperature sensor 35A and the oil temperature converted in the transmission controller 30 are inverted. The smaller the output value of the ATF oil temperature sensor 35A, the higher the oil temperature.

By the way, ATF oil temperature has the characteristics that a rise rate is large, when temperature is low. For example, in the so-called cold start after a long time elapses after the engine 10 is stopped, the ATF oil temperature rises due to the heat generated by the engine 10 as a heat source.

In this case, a difference may occur between the actual oil temperature and the oil temperature measured by the ATF oil temperature sensor 35A by the filter processing of the transmission controller 30. In order to make this deviation small and to acquire an ATF oil temperature correctly, it is preferable that a response does not delay too much by a filter process.

On the other hand, after the automatic transmission 20 is sufficiently warmed by the engine 10 and the ATF oil temperature rises above a certain temperature, the variation of the ATF oil temperature becomes small. In this case, in order to prevent the influence by noise, it is preferable to delay the response by the filter process.

Therefore, the transmission controller 30 of this embodiment can reduce the difference of estimated oil temperature and actual oil temperature based on the output value of ATF oil temperature sensor 35A by the characteristic structure as demonstrated below. At the same time, it was configured to prevent the influence of noise.

2 is a flowchart of the estimation process of the ATF oil temperature executed by the transmission controller 30 of the present embodiment.

This flowchart is executed by the transmission controller 30 at predetermined intervals (for example, at 10 ms intervals).

First, the transmission controller 30 acquires the value output from the ATF oil temperature sensor 35A (S10). The transmission controller 30 converts the oil temperature to the oil temperature using the above-described conversion table based on the obtained output value of the ATF oil temperature sensor.

Next, the transmission controller 30 determines whether the oil temperature corresponding to this output value is more than the predetermined threshold value T1 (S20). If it is determined that the oil temperature is equal to or higher than the threshold T1, the flow proceeds to step S60. If it is determined that the oil temperature is less than the threshold value T1, the flow proceeds to step S30.

In step S30, the transmission controller 30 determines whether the oil temperature corresponding to the output value is less than the predetermined threshold T2. If it is determined that the oil temperature is less than the threshold value T1, the flow proceeds to step S40. If it is determined that the oil temperature is equal to or higher than the threshold T1, the flow proceeds to step S50.

In step S40 to S60, the filter process performed with respect to the acquired output value is performed.

Specifically, when the oil temperature corresponding to the acquired output value is less than the threshold value T2, the transmission controller 30 performs the low temperature side filter process on the acquired output value in step S40.

The low temperature side filter process performs a weighted average process of weighted averaging the output value obtained this time and the output value obtained when the present flowchart was executed last time. At this time, a weighted average is performed so that the delay of the response to the fluctuation of the oil temperature is smaller than that of the high temperature side filter process described later.

Specifically, the output value Tt after the filter process is obtained by the following equation (1) using the output value T (n) obtained this time and the output value T (n-1) obtained last time.

Where k and l are weighting factors.

In this equation (1), by appropriately setting the weighting coefficients (k, l), the variation in the output value is delayed in a predetermined response so that the deviation from the actual oil temperature is reduced.

When the oil temperature corresponding to the acquired output value is equal to or greater than the threshold T2 or less than the threshold T1, the transmission controller 30 determines the filter processing (high temperature side filter processing or low temperature) determined when the present flowchart was executed in step S50 last time. Side filter processing) on the obtained output value.

In addition, when the oil temperature corresponding to the acquired output value is more than the threshold value T1, the transmission controller 30 performs a high temperature side filter process with respect to the acquired output value in step S60.

In the high temperature side filter process, in the weighted average process of the output value acquired this time and the output value acquired last time, it sets so that the response to the fluctuation of oil temperature may be delayed rather than the low temperature side filter process mentioned above.

Specifically, in the above formula (1), the weighting coefficient k of the output value T (n) obtained this time is made lighter than the weighting coefficient k in the low temperature side filter process in step S40. , Set the weighting factors (k and l). In this way, the influence of noise is prevented by delaying the change in the output value rather than the response of the low temperature side filter process.

In this way, the transmission controller 30 performs the high temperature side filter process or the low temperature side filter process with respect to the acquired output value, and a filter processing means is comprised. Moreover, when the temperature corresponding to the acquired output value is more than the threshold value T1, the filter process (high temperature side filter process) which delays a response more than the filter process (low temperature side filter process) performed when it is less than the threshold value T2. By performing the above, the filter switching means is configured.

Next, the transmission controller 30 uses the conversion table as described above on the basis of the output value Tt subjected to the filter process by the processes of these steps S40 to S60, to the oil temperature corresponding to the voltage of the output value. The conversion is made (S70). This converted oil temperature becomes an estimate of the current ATF oil temperature. After this process, the process by this flowchart is complete | finished, and it transfers to another control.

Like the oil temperature estimation process shown in FIG. 2, the transmission controller 30 estimates the oil temperature based on the output value obtained from the ATF oil temperature sensor 35A, so that the oil temperature estimating apparatus is configured.

In addition, in step S40-S60, although the high temperature side filter process and the low temperature side filter process are switched, since switching only changes the weighting coefficients k and l, it estimates by the oil temperature estimated by this process, and the previous process. There is no case where a step occurs at the oil temperature.

In addition, when the process by this flowchart is performed after starting operation (when there is no previous output value), the initial value of step S20 and S30 is made into a low temperature side, and it sets so that a low temperature side filter process may be performed first.

3 is an explanatory diagram showing switching of the filter process in the estimation process of the ATF oil temperature by the transmission controller 30 of the present embodiment.

When the oil temperature corresponding to the output value of the ATF oil temperature sensor 35A is less than the threshold value T2, the low temperature side filter process is executed. Thereafter, even when the oil temperature rises gradually and exceeds the threshold T2, the low temperature side filter process continues. And when it becomes more than threshold value T1, it will switch to high temperature side filter process.

In addition, when oil temperature is more than the threshold value T1, a high temperature side filter process will be performed, and after that, when an oil temperature will fall gradually and it becomes below the threshold value T1, a high temperature side filter process will continue. And when it becomes below threshold T2, it will switch to low temperature side filter process.

By setting the hysteresis based on the threshold value T1 and the threshold value T2 in this manner, it is possible to prevent hunting that the control is changed in a short time due to the change in the output value of the ATF oil temperature sensor 35A.

As described above, in the embodiment of the present invention, the transmission controller 30 that controls the automatic transmission 20 estimates the oil temperature of the ATF of the automatic transmission 20 based on the output value of the ATF oil temperature sensor 35A. do.

At this time, if the temperature corresponding to the output value of the ATF oil temperature sensor 35A is greater than or equal to the threshold T1, the high temperature side filter process is performed, and if the temperature corresponding to the output value of the ATF oil temperature sensor 35A is less than the threshold T2. The low temperature side filter process is performed.

In this way, appropriate filter processing can be performed in the case where the oil temperature is low and high, by switching the filter processing in which the response delay state is different based on the output value from the oil temperature sensor.

That is, when oil temperature is low, a filter process can be performed so that a response may not be delayed too much with respect to the fluctuation | variation of the oil temperature with a large rise rate, and can isolate | separate with a real oil temperature. In addition, when the oil temperature is high, the filter process may be performed to delay the response to the oil temperature having a small fluctuation, thereby preventing the influence of noise.

In addition, since the hysteresis by the threshold value T1 and the threshold value T2 is set for switching of the filter process of the high temperature side and the low temperature side, the hunting of switching of a filter process can be prevented.

In addition, although embodiment of this invention demonstrated above demonstrated estimation of ATF oil temperature in the automatic transmission 20, it is not limited to this. If the temperature of the working fluid (eg, engine oil, power steering fluid, automatic transmission fluid, brake fluid, etc.) used in the vehicle is estimated based on the temperature sensor, the same applies. In addition, the present invention can be applied not only to the working fluid but also to the estimation of the temperature of the cooling water and the fuel.

In addition, in the embodiment of the present invention, in step S20 and S30 of the flowchart shown in FIG. 2, the filter process was switched based on the acquired output value, but based on the oil temperature estimated by the last oil temperature estimation process, the filter The processing may be switched.

In the embodiment of the present invention, the filter processing is realized by performing a weighted average process on the output value obtained last time and the output value obtained this time, but the present invention is not limited thereto. For example, any filter may be used as long as it delays the response to the change in the output value, such as a filter for removing the high frequency component such as the first-delay filter and delays the response to the change in the output value.

Moreover, in embodiment of this invention, when oil temperature fell gradually and it became below the threshold value T2 from the state whose oil temperature is T1 or more, it switched to the low temperature side filter process. On the other hand, after performing a high temperature side filter process once, you may control so that it may not switch to a low temperature side filter process even if oil temperature falls and it becomes less than threshold value T2.

By controlling in this way, even if the oil temperature is temporarily lowered, it is highly likely that the oil temperature will rise to the high temperature side again while driving the vehicle, so that it is possible to prioritize the prevention of the influence by noise. When the vehicle stops driving, control is switched so that the low temperature side filter process can be executed.

This invention is not limited to the above-mentioned embodiment, Of course, various changes and improvement which can be achieved within the range of the technical idea are included.

10: engine
12: torque converter
20: automatic transmission
30: transmission controller (ATCU)
35A: ATF Oil Temperature Sensor

Claims (4)

An oil temperature sensor that outputs an output value corresponding to the oil temperature of the working oil used in the vehicle,
Filter processing means for performing first filter processing on the output value to delay a change in the output value in a predetermined response;
Filter switching means for switching the processing performed by the filter processing means to a second filter processing whose response is delayed from the first filter processing when the oil temperature corresponding to the output value is equal to or greater than a predetermined threshold value;
And an oil temperature estimating means for estimating an oil temperature of the working oil based on the output value on which the first or second filter processing is performed. The apparatus for estimating oil temperature according to claim 1, wherein the threshold value is set so that the filter switching means has hysteresis. The oil filter according to claim 1 or 2, wherein the filter processing means delays the variation of the output value in a predetermined response by performing a weighted average between the output value obtained this time and the output value acquired last time. Estimation device. Acquire the output value from the oil temperature sensor which outputs the output value according to the oil temperature of the hydraulic oil used for the vehicle,
When the oil temperature corresponding to the obtained output value is less than the first threshold value, the first filter process is performed to delay the variation of the output value in a predetermined response with respect to the output value,
When the oil temperature corresponding to the acquired output value is equal to or greater than the second threshold value larger than the first threshold value, the second filter process is performed on the output value with a delay in response to the first filter process,
When the oil temperature corresponding to the acquired output value is equal to or greater than the first threshold and less than the second threshold, the first or second filter processing performed last time is performed.
An oil temperature estimation method, characterized in that the oil temperature of the operating oil is estimated based on the output value of the first or second filter processing.

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