JP2023115605A - Foreign matter quantity estimation system - Google Patents

Abstract

To estimate a quantity of foreign matters in a working fluid at a low cost without using a foreign matter quantity detection sensor.SOLUTION: A foreign matter quantity estimation system estimates a quantity of foreign matters mixed in a working fluid which is used in a drive transmission device connected to a prime motor for a vehicle. The foreign matter quantity estimation system comprises: a drag torque acquisition unit for acquiring drag torque in an oil pump installed in the drive transmission device; a calculation unit for calculating a change amount of the density of the working fluid on the basis of the drag torque acquired by the drag torque acquisition unit at a first time point, and the drag torque acquired by the drag torque acquisition unit at a second time point with a prescribed period left from the first time point; and an estimation unit for estimating the quantity of the foreign matters mixed in the working fluid on the basis of a change amount of the density of the working fluid which is calculated by the calculation unit.SELECTED DRAWING: Figure 1

Description

The present invention relates to a foreign matter amount estimation system.

2. Description of the Related Art Conventionally, there has been known a control device for an automatic transmission provided with a sensor for detecting the amount of foreign matter mixed in hydraulic fluid used in a drive transmission device connected to a prime mover of a vehicle (see, for example, Patent Document 1). ). If the degree of contamination of the hydraulic oil can be detected by the sensor, it can be used as a guideline for replacement of the hydraulic oil.

JP-A-7-91534

However, mounting the sensor increases the manufacturing cost of the drive transmission device and the vehicle.

Therefore, an object of the foreign matter amount estimation system disclosed in the present specification is to estimate the amount of foreign matter in hydraulic oil at low cost without using a sensor for detecting the amount of foreign matter.

A foreign matter amount estimation system disclosed in the present specification is a foreign matter amount estimation system for estimating the amount of foreign matter mixed in hydraulic fluid used in a drive transmission device connected to a prime mover for a vehicle. a drag torque acquisition unit that acquires the drag torque in the oil pump installed in the drag torque acquired by the drag torque acquisition unit at a first time point; a calculation unit that calculates a change in the density of the hydraulic oil based on the drag torque acquired by the drag torque acquisition unit at the time point of; and a change in the density of the hydraulic oil calculated by the calculation unit and an estimating unit for estimating the amount of foreign matter mixed in the hydraulic oil based on the amount of the foreign matter.

According to the foreign matter amount estimation system disclosed in this specification, the amount of foreign matter in hydraulic oil can be estimated at low cost without using a sensor for detecting the amount of foreign matter.

FIG. 1 is an explanatory diagram showing a schematic configuration of the foreign matter amount estimation system of the embodiment. FIG. 2 is an example of a flow chart showing the process of inspecting the state of the ATF by the foreign matter amount estimation system of the embodiment. FIG. 3 is an example of a flow chart showing detailed steps of foreign matter amount estimation according to the embodiment. FIG. 4 is an example of a graph showing the relationship between engine speed and engine torque. FIG. 5 is an example of a graph showing the relationship between the hydraulic oil (ATF) density and the amount of foreign matter in the ATF. FIG. 6 is a diagram showing an example of a message displayed on a display unit provided in a vehicle.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, in the drawings, the dimensions, ratios, etc. of each part may not be illustrated so as to completely match the actual ones. In some drawings, details may be omitted.

(embodiment)
[Foreign matter amount estimation system]
First, referring to FIG. 1, a schematic configuration of a foreign matter amount estimation system 1000 according to an embodiment will be described. The system 1000 for estimating the amount of foreign matter is detected by an inspection device 50 installed in, for example, a maintenance shop for the vehicle 100. The foreign matter amount estimating system 1000 detects whether foreign matter is mixed in the hydraulic fluid (hereinafter referred to as ATF: Automatic Transmission Fluid) used in the drive transmission device 4 provided in the vehicle 100. Estimate the amount of foreign matter

<Vehicle>
The vehicle 100 includes an engine 2 and a drive transmission device 4 connected to the engine 2 for transmitting power of the engine 2 to wheels (not shown). The engine 2 is an internal combustion engine and an example of a prime mover. A motor can also be employed as the prime mover.

The drive transmission device 4 includes a torque converter 6 and an automatic transmission 8 . The torque converter 6 and the automatic transmission 8 are housed inside the case 4a. ATF is supplied in the case 4a. The drive transmission device 4 converts the rotation of a crankshaft (not shown) included in the engine 2 into a desired number of revolutions and transmits it to the wheels. The automatic transmission 8 includes various rotating members forming a planetary gear mechanism inside, and friction engagement mechanisms such as clutches and brakes. The automatic transmission mechanism 8 selects a rotating member that forms a power transmission path by changing the combination of engagement and disengagement states of the friction engagement mechanism, and realizes a desired output state. The internal structure of the automatic transmission 8 employs a conventionally known structure, and therefore detailed description thereof will be omitted here. Also, since the structure of the torque converter 6 is also conventionally known, a detailed description thereof will be omitted.

An oil pan 10 is provided below the drive transmission device 4 . The oil pan 10 stores ATF which is supplied to the case 4a and circulates between the case 4a and the case 4a. A valve body 12 is installed in the oil pan 10 . The valve body 12 is provided with complicated passages for supplying ATF at a desired pressure to each part in the drive transmission device 4 . An oil passage 14 is connected to the valve body 12 and extends toward the inside of the case 4a. The oil passage 14 is connected to the frictional engagement mechanism within the automatic transmission 8, and the ATF supplied through the oil passage 14 operates the frictional engagement mechanism by its oil pressure.

An oil pump 16 is provided in the oil passage 14 . The oil pump 16 is a mechanical pump that is driven by the driving force of the engine 2 . The oil pump 16 is incorporated within the case 4 a and arranged between the torque converter 6 and the automatic transmission 8 .

An oil passage 18 extends from the automatic transmission 8 . The oil passage 18 returns the ATF supplied to the automatic transmission 8 to the oil pan 10 .

The oil pan 10 is provided with an oil temperature sensor 20 that measures the temperature of the ATF (oil temperature). The oil temperature measured by the oil temperature sensor 20 is referred to in order to keep the estimation conditions constant when estimating the amount of foreign matter in the ATF. The engine 2 is provided with a torque sensor 22 that detects torque in the crankshaft. The torque value detected by the torque sensor 22 is used as the engine torque T when estimating the amount of foreign matter in the ATF.

The vehicle 100 includes a display section 102 capable of displaying various information. The display unit 102 displays, for example, a notice that the maintenance time for the vehicle 100 is approaching, a notification of a defective part, and the like.

<Inspection device>
The inspection device 50 is installed in a maintenance shop or the like, and is connected to the vehicle 100 when estimating the amount of foreign matter in the ATF. The connection format may be a wired connection using a cable or a wireless connection. By being connected to the vehicle 100 , the inspection device 50 can acquire the measurement value of the torque sensor 22 and the oil temperature value measured by the oil temperature sensor 20 . The inspection device 50 includes a drag torque acquisition section 52 , a calculation section 54 , an estimation section 56 and a comparison section 58 . The inspection device 50 includes a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), backup RAM and other storage devices.

In the inspection device 50, arithmetic processing and various controls are executed based on programs and maps stored in the CPU, ROM, and other storage devices. Further, the functions of the drag torque acquisition section 52, the calculation section 54, and the estimation section 56 are realized by cooperation of programs stored in the CPU, ROM, and other storage devices. The RAM is a memory that temporarily stores calculation results by the CPU and data input from various sensors, etc. The backup RAM is a non-volatile memory that stores data to be saved when the engine 2 is stopped. .

As will be described in detail later, when estimating the amount of foreign matter in the ATF, the number of rotations of the engine 2 and the temperature of the ATF are adjusted to keep the conditions for obtaining the values used for estimation constant. Ensure that the operating conditions, including The inspection device 50 can control the operating state of the engine 2 when estimating the amount of foreign matter, and issue an instruction so that the rotational speed of the engine 2 and the temperature of the ATF meet predetermined operating conditions. That is, the inspection device 50 can issue an instruction to put the vehicle 100 into the inspection mode.

[Estimation of Foreign Matter Amount]
Next, estimation of the amount of foreign matter in the ATF by the foreign matter amount estimation system 1000 will be described with reference to FIGS. 2 to 5. FIG.

First, in step S10, the inspection device 50 determines whether or not there is an instruction to estimate the amount of foreign matter in the ATF. In this embodiment, the vehicle 100 is brought to a maintenance shop, the vehicle 100 is connected to the inspection device 50, and the maintenance staff operates the inspection device 50 to start foreign object amount estimation. A determination (YES determination) is made. Note that the estimation of the amount of foreign matter in the ATF may be performed at any timing, or may be automatically performed at the timing of the first maintenance warehousing after a predetermined period or a predetermined mileage has been exceeded. good. Implementation at an arbitrary timing is not limited to cases based on instructions from the user of the vehicle 100 or maintenance staff, but for example, it is implemented as part of a pre-vehicle check mode before running on a circuit or a check mode after running on a circuit. There are cases. Further, examples of the case of automatic implementation include inspection at the time of periodic inspection, and inspection at fixed distance travel such as 100,000 km travel and 200,000 km travel. If the inspection apparatus 50 makes a negative determination (NO determination) in step S10, the process returns, and the process of step S10 is repeated.

After making an affirmative determination in step S10, the inspection device 50 determines in step S20 whether or not the state of the vehicle 100 is such that the amount of foreign matter can be obtained. Specifically, the inspection device 50 confirms whether or not the vehicle 100 is in a state (maintenance mode) in which maintenance can be safely performed, such as when the vehicle 100 cannot travel. It should be noted that the inspection device 50 may display on its own operation screen or on the display unit 102 of the vehicle 100 that it is in the maintenance mode, so as to notify the person in charge of maintenance. can. If the determination in step S20 is affirmative, the inspection device 50 proceeds to step S30. On the other hand, if NO is determined in step S20, the process from step S10 is repeated.

In step S30, the inspection device 50 starts operating the engine 2 so that the conditions for obtaining the amount of foreign matter in the ATF are satisfied. Here, driving does not mean operating the vehicle 100, but an operating state in which the drive transmission device 4 is in a non-driving state, that is, in a neutral state, and the engine speed is increased to a predetermined speed. That is. This is because, as will be described in detail later, the amount of foreign matter is estimated by comparing the ATF densities acquired at predetermined intervals and based on the amount of change. for getting under.

In step S40 that follows step S30, the inspection device 50 estimates the amount of foreign matter. A process for estimating the amount of foreign matter is defined by a subroutine. This subroutine will be described with reference to the flowchart shown in FIG.

In step S41, the inspection device 50 determines whether or not the constant oil temperature is maintained. Here, the ATF oil temperature is a temperature preset with the estimation of the amount of foreign matter as one of the execution conditions, and the inspection device 50 keeps the ATF oil temperature constant at this preset temperature in step S41. It is determined whether or not Oil temperature is detected by an oil temperature sensor 20 . When the inspection device 50 makes an affirmative determination in step S41, the process proceeds to step S42. On the other hand, if a negative determination is made in step S41, the process of step S41 is repeated until an affirmative determination is made in step S41.

In step S42, the inspection device 50 determines whether or not the constant engine speed is maintained. This is to determine whether or not the rotation speed of the engine 2, which has been increased to the predetermined rotation speed started in step S30, is in a stable state. By keeping the engine speed constant, the rotational speed of the mechanical oil pump 16 can be kept constant. As a result, together with the constant oil temperature condition determined in step S43, the density value of the ATF can be obtained under the same condition each time. If the determination in step S42 is affirmative, the inspection device 50 proceeds to step S43. On the other hand, if a negative determination is made in step S42, the process of step S42 is repeated until an affirmative determination is made in step S43, that is, until the engine speed stabilizes.

In step S43, the inspection device 50 acquires the engine torque T. FIG. In this embodiment, the engine 2 includes the torque sensor 22 , so the engine torque T can be obtained as a value detected by the torque sensor 22 . The torque sensor 22 acquires the engine torque T by measuring the strain amount of the crankshaft in the engine 2 in operation. If the engine 2 does not have the torque sensor 22, the engine torque can be obtained from the engine speed based on the graph in FIG. 4 showing the relationship between the engine speed and the engine torque. Also, when a motor is employed as the prime mover, the torque value of the motor is acquired instead of the engine torque T, but the torque value of the motor can be estimated based on the current value supplied to the motor. .

In step S<b>44 that follows step S<b>43 , the drag torque acquisition unit 52 provided in the inspection device 50 acquires the drag torque in the oil pump 16 . Here, the drag torque is the torque required to rotate the drive system in the state where no load is applied, and refers to the rotational resistance of the drive system. The drag torque is a combination of the resistance and loss of each part of the engine 2 and the drive transmission device 4 . For example, the drag torque includes meshing loss of gears incorporated in the automatic transmission 8, rotation loss of fluid couplings, rolling resistance of bearings, and the like. These factors can be estimated to be constant when the engine 2 is in steady operation with a constant rotation speed.

In this embodiment, attention is paid to the drag torque in the oil pump 16, and the change in the ATF density is calculated based on the change in the drag torque in the oil pump 16. FIG. Therefore, the drag torque acquisition unit 52 obtains from the engine torque T the drag such as meshing loss of gears incorporated in the automatic transmission 8 derived from other than the oil pump 16, rotation loss of fluid couplings, rolling resistance of bearings, and the like. Exclude the factors involved in torque. That is, by subtracting factors other than the drag torque in the oil pump 16 from the engine torque T, the drag torque in the oil pump 16 is obtained. The acquired drag torque in the oil pump 16 corresponds to the drive input Pa to the oil pump 16 .

In the present embodiment, the drag torque in the oil pump 16 is acquired at a first time point and at a second time point after a predetermined period from the first time point. The first point in time is the point at which the amount of foreign matter was estimated last time, and the second point in time is the point at which the amount of foreign matter is estimated this time.

The drag torque in the oil pump 16 at the first time is taken as the drive input Pa1 to the oil pump 16 at the first time. Also, the drag torque in the oil pump 16 at the second time is taken as the drive input Pa2 to the oil pump 16 at the second time. It should be noted that drive input Pa1 and drive input Pa2 may be corrected in consideration of the travel distance of vehicle 100 and deterioration of oil pump 16 over time.

After estimating the drag torque in step S44, the calculation unit 54 included in the inspection device 50 proceeds to step S45. In step S45, an operation is performed to obtain the amount of change in the ATF density ρ.

Here, the calculation of the amount of change in the density ρ of the ATF using the driving input Pa1 and the driving input Pa2 will be described in detail.

First, the pump efficiency η of the oil pump 16 can be expressed by the following equation (1) using the drive input Pa [W] and the oil power Pw [W] of the oil pump 16 .

但し、本実施形態では、最終的に密度の変化分を得るための式（７）には表れないため、Ｐｗの具体的な数値を求めることは不要である。 Here, the oil power Pw [W] is the energy with which the ATF is obtained per unit time by the oil pump 16, and is calculated by multiplying the flow rate of the ATF by the total pressure. Since total pressure = density x gravitational acceleration x pump head, values other than density ρ are constant, and considering that only density ρ is a variable, oil power Pw [W] is a variable of density ρ. Therefore, the oil power Pw [W] can be expressed by the following equation (2).

However, in the present embodiment, it is not necessary to obtain a specific numerical value of Pw because it does not appear in equation (7) for finally obtaining the amount of change in density.

Calculation of the change in density ρ from the first point in time to the second point in time will now be described. In the following description, the ATF density at the first point in time is ρ1, and the ATF density at the second point in time is ρ2.

ここで、Ｐｗ１は第１の時点におけるオイル動力、Ｐｗ２は第２の時点におけるオイル動力である。 Assuming that the pump efficiency η and the operating conditions of the engine 2 are unchanged at the first time point and the second time point, the following equation (3) holds.

Here, Pw1 is the oil power at the first point in time, and Pw2 is the oil power at the second point in time.

By transforming equation (3), Pw1, Pa1, Pw2 and Pa2 can be expressed as in equation (4) below.

Pw1 and Pw2 can be expressed as in the following formula (5) based on the formula (2).

The following equation (6) can be obtained by substituting Pw1 and Pw2 in equation (5) for Pw1 and Pw2 in equation (4).

Then, the ATF density ρ2 at the second point in time can be expressed by transforming the equation (6) into the following equation (7).

According to the equation (7), the ATF density ρ2 at the second point in time is the ratio of the drive input Pa1 at the first point in time to the drive input Pa2 at the second point in time, and the ATF density ρ1 at the first point in time. can be expressed in a multiplied form. Here, since the ATF density ρ1 and the drive input Pa1 at the first point in time are known values obtained at the first point in time, the drag torque in the oil pump 16 is obtained at the second point in time, and the drive input By obtaining Pa2, the density ρ2 can be obtained. Thereby, the amount of change in the ATF density ρ can be calculated.

When the ATF is replaced with a new one, the time of replacement is defined as the first point in time, and the density ρ of the new ATF is defined as the density ρ1 at the first point in time. Further, the drag torque in the oil pump 16 with the ATF replaced with a new one is acquired in advance by simulation or adaptation, and the drive input Pa1 based on this is stored. As a result, at the second point in time after the ATF is replaced with a new one, the above-described calculation can be performed to calculate changes in the density ρ2 and the density ρ of the ATF at the second point in time.

In step S46 that follows step S45, the estimation unit 56 provided in the inspection apparatus 50 estimates the amount of foreign matter based on the ATF density ρ2 at the second point in time calculated in step S44. Specifically, the estimating unit 56 applies the ATF density ρ2 to the graph (map) shown in FIG. 5 to obtain the value of the foreign matter amount. As shown in FIG. 5, there is a correlation between the ATF density ρ and the amount of foreign matter. That is, the density ρ increases as the amount of foreign matter increases. Therefore, the higher the density ρ, the greater the amount of foreign matter, and if the value of the density ρ can be known, the amount of foreign matter can be estimated. This completes the estimation of the amount of foreign matter. After completing step S46, the inspection device 50 proceeds to step S50 in the flowchart shown in FIG.

In step S50, the comparison unit 58 provided in the inspection device 50 determines whether or not the amount of foreign matter estimated in step S46 is equal to or greater than a preset reference value. Here, the reference value is set as a foreign matter amount value for which replacement of the ATF is recommended.

If the determination in step S50 is affirmative, the inspection device 50 proceeds to step S60. In step S<b>50 , inspection device 50 causes display unit 102 provided in vehicle 100 to display a foreign object discharge instruction. For example, as shown in FIG. 6, the display unit 102 can display "Please replace ATF" and "Recommend performing refresh maintenance". This promotes the discharge of foreign matter. In addition, the inspection device 50 displays a message such as "Please refrain from sports driving" on the display unit 102 to prevent the driving state from increasing the amount of foreign substances in the ATF. The information displayed on the display unit 102 may be displayed on a screen or the like provided in the inspection device 50 .

Information used for estimating the amount of foreign matter in the ATF, the estimated amount of foreign matter, the timing of the estimation, the ATF replacement history, etc. can be stored in the inspection device 50 for each vehicle. By storing these in chronological order, the next foreign matter amount can be estimated, and the state of the vehicle 100 can be managed. It should be noted that the vehicle 100 may have the functions of the inspection device 50 .

According to the present embodiment, by using the drag torque acquired at the first time point and the drag torque acquired at the second time point, the ATF can be detected at low cost without using a sensor for detecting the amount of foreign matter. of foreign matter can be estimated. As a result, the manufacturing costs of the drive transmission device 4 and the vehicle 100 can be suppressed.

The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited to these. Various modifications of these examples are within the scope of the present invention, and furthermore, the present invention can be modified. It is self-evident from the above description that many other embodiments are possible within the scope.

2 engine 4 drive transmission device 4a case 6 torque converter 8 automatic transmission 10 oil pan 12 valve body 14, 18 oil passage 16 oil pump 20 oil temperature sensor 22 torque sensor 50 inspection device 52 drag torque acquisition unit 54 calculation unit 56 estimation unit 58 comparison unit 100 vehicle 102 display unit

Claims (1)

A foreign matter amount estimation system for estimating the amount of foreign matter mixed in hydraulic oil used in a drive transmission device connected to a prime mover for a vehicle,
a drag torque acquisition unit that acquires a drag torque in an oil pump installed in the drive transmission device;
Based on the drag torque acquired by the drag torque acquisition unit at a first time point and the drag torque acquired by the drag torque acquisition unit at a second time point after a predetermined period from the first time point , a calculation unit for calculating a change in the density of the hydraulic oil;
an estimating unit that estimates the amount of foreign matter mixed in the hydraulic oil based on the amount of change in the density of the hydraulic oil calculated by the calculation unit;
foreign matter amount estimation system.

Images