Drive shaft boot temperature estimation device

Abstract

Estimate the temperature of the drive shaft boot. [Solution] A drive shaft boot temperature estimation device for use in an automobile equipped with a grill shutter that is attached to the grill in front of the radiator and can be opened and closed, and a drive shaft boot, the device estimates the temperature of the drive shaft boot based on a trained model obtained by machine learning, which takes as input variables a first parameter that reflects the temperature around the drive shaft boot, a second parameter that reflects the temperature of a heat source close to the drive shaft boot, and a third parameter that has at least one of the vehicle speed and the open / closed state of the grill shutter, and as an output variable the temperature of the drive shaft boot, and the first, second, and third parameters.

Description

Technical Field

[0001] The present disclosure relates to a temperature estimation device for a drive shaft boot.

Background Art

[0002] Conventionally, as an automobile, there has been proposed one including a drive shaft boot, a joint that connects either an input shaft of a driving wheel of the vehicle and a drive shaft, and a heat pipe extending from an end portion of the drive shaft (see, for example, Patent Document 1). In this automobile, heat generated at the joint is radiated by the heat pipe, thereby suppressing a temperature rise of the drive shaft boot. Thereby, deterioration of the drive shaft boot is suppressed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described automobile, when a heat radiation device for radiating heat from surrounding heat sources is provided, the number of parts increases. As a method for suppressing an increase in the number of parts, a method of suppressing a temperature rise of the drive shaft by controlling surrounding heat sources according to the temperature of the drive shaft is conceivable. However, in the above-described automobile, since the temperature of the drive shaft boot is not estimated, such a method cannot be used. Therefore, estimating the temperature of the drive shaft boot has been recognized as an important problem.

[0005] The temperature estimation device for a drive shaft boot of the present disclosure has a main object of estimating the temperature of the drive shaft boot.

Means for Solving the Problems

[0006] The drive shaft boot temperature estimation device of this disclosure employs the following means to achieve the main objective described above.

[0007] The drive shaft boot temperature estimation device of this disclosure is A drive shaft boot temperature estimation device for use in an automobile equipped with a grille shutter that is attached to the front grille of the radiator and can be opened and closed, and a drive shaft boot, which estimates the temperature of the drive shaft boot, A trained model obtained by machine learning takes the following as input variables: a first parameter that reflects the temperature around the drive shaft boot; a second parameter that reflects the temperature of a heat source close to the drive shaft boot; and a third parameter that has at least one of the vehicle speed and the open / closed state of the grill shutter; and the temperature of the drive shaft boot as the output variable; and estimates the temperature of the drive shaft boot based on the first, second, and third parameters. This is the gist of it.

[0008] The drive shaft boot temperature estimation device of this disclosure estimates the drive shaft boot temperature based on a trained model obtained by machine learning, which takes the following as input variables: a first parameter that reflects the temperature around the drive shaft boot, a second parameter that reflects the temperature of a heat source close to the drive shaft boot, and a third parameter that has at least one of the vehicle speed and the open / closed state of the grill shutter, and the drive shaft boot temperature as the output variable, and the first, second, and third parameters. As a result, the drive shaft boot temperature can be estimated. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing the configuration of the powertrain of an automobile 20 equipped with a temperature estimation device according to the embodiment of this disclosure, as viewed from the rear. [Figure 2] This is an explanatory diagram illustrating an example of how to create a pre-trained model. [Figure 3] This flowchart shows an example of an estimation routine executed by ECU50. [Modes for carrying out the invention]

[0010] Embodiments of this disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram showing the configuration of the powertrain of an automobile 20 equipped with a temperature estimation device according to the embodiment of this disclosure, as viewed from the rear. As shown in the figure, the automobile 20 of the embodiment includes an engine 22, a transaxle 26, drive shafts 30r and 30l, a grille shutter 46, and an electronic control unit (hereinafter referred to as "ECU") 50. In this embodiment, the ECU 50 corresponds to the "temperature estimation device".

[0011] Engine 22 is configured as an internal combustion engine that uses gasoline as fuel to produce power. This engine 22 draws air from the intake port into the air cleaner, circulates the air cleaned by the air cleaner into the intake manifold, and injects gasoline from the fuel injector. The mixture of air and fuel is then drawn into the combustion chamber via the intake valve and exploded by an electric spark from the spark plug, converting the reciprocating motion of the piston pushed down by the energy into the rotational motion of the crankshaft. The exhaust from the combustion chamber is discharged into the outside air via a purification device having a purification catalyst (three-way catalyst) that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx), and an exhaust pipe 22e. The engine 22 is operated and controlled by the ECU 50.

[0012] The transaxle 26, although not shown in the diagram, includes a transmission that shifts and outputs power from the engine 22, and a differential gear. The transaxle 26 is controlled by the ECU 50.

[0013] The drive shaft 30r is connected at one end to the differential gear (not shown) of the transaxle 26 via an inboard joint (not shown) and connecting shaft 36r housed in an inboard 32r and inner drive shaft boot 34r, and at the other end to the right wheel (not shown) via an outboard joint (not shown) housed in an outboard 40r and outer drive shaft boot 38r. The inboard 32r is attached to the engine 22 by a bracket 42. The inboard 32r, inner drive shaft boot 34r, connecting shaft 36r, and bracket 42 are located behind the exhaust pipe 22e of the engine 22.

[0014] The drive shaft 30l is connected at one end to the differential gear (not shown) of the transaxle 26 via an inboard joint (not shown) housed in the inboard 32l and inner drive shaft boot 34l, and at the other end to the left wheel (not shown) via an outboard joint (not shown) housed in the outboard 40l and outer drive shaft boot 38l.

[0015] The grill shutter 46 is mounted on the grill in front of the radiator (not shown) and is configured to be openable and closable by an actuator 48. The actuator 48 is controlled by an ECU 50.

[0016] The ECU50 is configured as a microprocessor centered on a CPU, and in addition to the CPU, it is equipped with ROM for storing processing programs, RAM for temporarily storing data, flash memory for storing data, and input / output ports. Signals from various sensors are input to the ECU50 via the input ports. Examples of signals input to the ECU50 include the engine oil temperature Toe from temperature sensor 22t for detecting the temperature of the engine oil that lubricates and cools the engine 22, the exhaust pipe temperature Tex from temperature sensor 22et for detecting the temperature of the exhaust pipe 22e, the transmission oil temperature Tom from temperature sensor 26t for detecting the temperature of the transmission oil that lubricates and cools the transmission of the transaxle 26, the ambient temperature Tatm from temperature sensor 52 for detecting the ambient temperature, and the vehicle speed V from vehicle speed sensor 54 for detecting the vehicle speed. Various control signals are output from the ECU50 via the output ports. Examples of signals output from the ECU50 include control signals for operating the engine 22, control signals for controlling the transaxle 26, and control signals for controlling the actuator 48.

[0017] The ECU 50 controls the operation of the engine 22 based on the opening of the accelerator pedal and the vehicle speed V, and controls the actuator 48 to open and close the grill shutter 46 based on the coolant temperature of the engine 22.

[0018] The ECU 50 stores in ROM a trained model obtained through machine learning, with the first, second, and third parameters P1, P2, and P3 as input variables (inputs to the input layer) and the drive shaft boot temperature Tdb, which represents the temperature of the inner drive shaft boot 34r, as an output variable (output to the output layer). The first parameter P1 is a parameter that reflects the temperature around the inner drive shaft boot 34r and includes the exhaust pipe temperature Tex and the ambient temperature Tatm. The second parameter P2 is a parameter that reflects the temperature from a heat source close to the inner drive shaft boot 34r and includes the engine oil temperature Toe and the transmission oil temperature Tom of the engine 22. The third parameter P3 includes the vehicle speed V and the open / closed state of the grill shutter 46. In this machine learning, the tester attaches a temperature sensor to the inner drive shaft boot 34r of the test vehicle and drives the test vehicle multiple times on roads, test courses, and chassis dynamometers. The ECU50 acquires multiple datasets at predetermined intervals during driving, each dataset containing the first, second, and third parameters P1, P2, and P3, and the drive shaft boot temperature Tdb. Once the ECU50 has acquired the number of datasets necessary to construct a highly accurate neural network, it creates a trained model using a neural network that takes the first, second, and third parameters P1, P2, and P3 as input variables and the drive shaft boot temperature Tdb as the output variable, as shown in Figure 2, and stores it in ROM. The first parameter P1 is used as an input variable because the temperature around the inner drive shaft boot 34r affects the drive shaft boot temperature Tdb. The second parameter P2 is used as an input variable because the temperature of a heat source close to the inner drive shaft boot 34r affects the drive shaft boot temperature Tdb. The third parameter P3 is used as an input variable because the vehicle speed V and the open / closed state of the grill shutter 46 affect the drive shaft boot temperature Tdb. Therefore, the trained model thus created is a highly accurate model. Note that the temperature sensor for detecting the temperature of the inner drive shaft boot 34r is installed only on test vehicles and is not installed on vehicles that are actually sold.

[0019] Next, the operation of the automobile 20 equipped with the temperature estimation device of the embodiment thus configured will be described, particularly the operation when estimating the drive shaft boot temperature Tdb. FIG. 3 is a flowchart showing an example of an estimation routine executed by the ECU 50. This routine is executed at predetermined time intervals while the automobile 20 is running.

[0020] When this routine is executed, the CPU of the ECU 50 inputs the first, second, and third parameters P1, P2, and P3 (S100).

[0021] Then, using the learned model stored in the ROM in advance and the first, second, and third parameters P1, P2, and P3 in S100, the drive shaft boot temperature Tdb is estimated (S110), and this routine ends. By using the learned model created in advance by machine learning in this way, the drive shaft boot temperature Tdb can be estimated.

[0022] According to the automobile 20 equipped with the deposit amount estimation device of the present embodiment described above, by using a learned model created using a neural network with the first, second, and third parameters P1, P2, and P3 as input variables and the drive shaft boot temperature Tdb as an output variable, and the first, second, and third parameters P1, P2, and P3, the drive shaft boot temperature Tdb can be estimated.

[0023] In the above-described embodiment, the operation when estimating the temperature of the inner drive shaft boot 34r has been described, but the same method can also be used when estimating the temperatures of the inner drive shaft boot 34l, the outer drive shaft boots 38r and 3dl.

[0024] In the embodiment described above, the first parameter P1 includes the exhaust pipe temperature Tex and the ambient temperature Tatm. However, the first parameter P1 only needs to include at least one of the exhaust pipe temperature Tex and the ambient temperature Tatm. Furthermore, the first parameter P1 may also include the temperature of other components that reflect the temperature around the inner drive shaft boot 34r, or it may include other parameters that reflect the temperature around the inner drive shaft boot 34r, such as power consumption.

[0025] In the embodiment described above, the second parameter P2 includes the engine oil temperature Toe and the transmission oil temperature Tom of the engine 22. However, the second parameter P2 only needs to include at least one of the engine oil temperature Toe and the transmission oil temperature Tom of the engine 22. The second parameter P2 may also include the temperature of other heat sources close to the inner drive shaft boot 34r, or it may include other parameters that reflect the temperature of heat sources close to the inner drive shaft boot 34r, such as power consumption.

[0026] In the embodiment described above, the third parameter P3 includes the vehicle speed V and the open / closed state of the grill shutter 46. However, the third parameter P3 only needs to include at least one of the vehicle speed V and the open / closed state of the grill shutter 46.

[0027] In the embodiment described above, the grill shutter 46 is configured to be driveable to open and close. The degree of opening may be adjustable when the grill shutter 46 is in the open position.

[0028] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem will be explained. In the embodiment, ECU50 corresponds to the "drive shaft boot temperature estimation device".

[0029] Furthermore, the correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem is merely an example to specifically explain the form in which the embodiment implements the invention described in the section on means for solving the problem, and does not limit the elements of the invention described in the section on means for solving the problem. In other words, the interpretation of the invention described in the section on means for solving the problem should be based on the description in that section, and the embodiment is merely one specific example of the invention described in the section on means for solving the problem.

[0030] The above describes the forms for implementing this disclosure using embodiments, but this disclosure is not limited in any way to these embodiments, and can of course be implemented in various forms without departing from the gist of this disclosure. [Industrial applicability]

[0031] This disclosure can be used in industries such as the manufacturing of drive shaft boot temperature estimation devices. [Explanation of Symbols]

[0032] 20 Automobile, 22 Engine, 22e Exhaust pipe, 22et Temperature sensor, 22t Temperature sensor, 26 Transaxle, 26t Temperature sensor, 30l Drive shaft, 30r Drive shaft, 32l Inboard, 32r Inboard, 34l Inner drive shaft boot, 34r Inner drive shaft boot, 36r Connecting shaft, 38l Outer drive shaft boot, 38r Outer drive shaft boot, 40l Outboard, 40r Outboard, 42 Bracket, 46 Grill shutter, 48 Actuator, 50 Electronic control unit (ECU), 52 Temperature sensor, 54 Vehicle speed sensor.

Claims

[Claim 1] A drive shaft boot temperature estimation device for use in an automobile equipped with a grill shutter that is attached to the grill in front of the radiator and can be opened and closed, and a drive shaft boot, which estimates the temperature of the drive shaft boot, A trained model obtained by machine learning takes the following as input variables: a first parameter that reflects the temperature around the drive shaft boot; a second parameter that reflects the temperature of a heat source close to the drive shaft boot; and a third parameter that has at least one of the vehicle speed and the open / closed state of the grill shutter; and the temperature of the drive shaft boot as the output variable; and estimates the temperature of the drive shaft boot based on the first, second, and third parameters. A device for estimating the temperature of drive shaft boots.

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