JP2024080500A - Deterioration parameter calculation system - Google Patents

Abstract

A deterioration parameter of a lubricating oil is calculated while suppressing an increase in the number of parts.
[Solution] A deterioration parameter calculation system calculates a deterioration parameter that indicates the degree of deterioration of lubricating oil that lubricates a gear mechanism having at least one gear and is stirred by the gear as the gear rotates, and calculates the deterioration parameter based on the torque and rotation speed of the rotating shaft, thereby making it possible to calculate the deterioration parameter of the lubricating oil while suppressing an increase in the number of parts.
[Selected figure] Figure 2

Description

The present invention relates to a degradation parameter calculation system.

Conventionally, a deterioration parameter calculation system of this type has been proposed that calculates the degree of deterioration of the lubricating oil that lubricates the engine, transmission, etc. based on the engine torque, the lubricating oil temperature, the vehicle speed, and the mileage (see, for example, Patent Document 1).

Patent No. 6753295

However, the deterioration parameter calculation system described above requires four pieces of information to calculate the lubricating oil deterioration parameters: engine torque, lubricating oil temperature, vehicle speed, and mileage. Therefore, in vehicles that do not use all four pieces of information to control the engine and transmission, new sensors must be installed to obtain the missing information, which increases the number of parts.

The main purpose of the degradation parameter calculation system of the present invention is to calculate the degradation parameters of lubricating oil while minimizing the increase in the number of parts.

The degradation parameter calculation system of the present invention employs the following means to achieve the above-mentioned primary objective. The degradation parameter calculation system of the present invention is a degradation parameter calculation system that lubricates a gear mechanism having at least one gear and connected to a rotating shaft, and calculates a degradation parameter indicating the degree of degradation of lubricating oil that is stirred by the gear as the gear rotates, and is characterized in that the degradation parameter is calculated based on the torque of the rotating shaft and the rotation speed of the rotating shaft.

1 is a diagram showing an outline of the configuration of an oil life determination system 10; 10 is a flowchart showing an example of a replacement determination routine. 13 is an example of a relationship between a deterioration parameter Pdg and an estimated kinetic viscosity value Kvest.

Next, we will explain how to implement the present invention using examples.

Figure 1 is a schematic diagram showing the configuration of an oil life determination system 10 equipped with a deterioration parameter calculation system as one embodiment of the present invention. As shown in the figure, the oil life determination system 10 includes a hybrid vehicle 20, a data accumulation server 80, an exchange determination server 82, and a dealer server 84.

The hybrid vehicle 20 includes an engine 22, a planetary gear 30, motors MG1 and MG2, inverters 41 and 42, a battery 50, and an electronic control unit (hereinafter referred to as "ECU") 70 that controls the entire vehicle.

The rotor of the motor MG1 is connected to the sun gear of the planetary gear 30, the drive shaft (rotating shaft) 36 connected to the drive wheels 39a, 39b via the differential gear 38 and the motor MG2 are connected to the ring gear, and the crankshaft 23 of the engine 22 is connected to the carrier. The planetary gear 30, the differential gear 38, and the motors MG1, MG2 are housed in the same case. Lubricating oil is stored in the bottom of this case. The differential gear 38 is partially immersed in the lubricating oil, and stirs the lubricating oil as it rotates. The differential gear 38 also scoops up the lubricating oil and sprays it on the planetary gear 30 and the motors MG1, MG2 to cool the planetary gear 30 and the motors MG1, MG2. The inverters 41, 42 are connected to the battery 50 via the power line 54. The motors MG1 and MG2 are driven to rotate by the ECU 70 controlling the switching of a plurality of switching elements (not shown) of the inverters 41 and 42. The ECU 70 includes a microcomputer having a CPU, ROM, RAM, flash memory, input/output ports, and communication ports. The ECU 70 receives inputs of signals from various sensors necessary for controlling the operation of the engine 22, such as the vehicle speed V from the vehicle speed sensor 72 and the accelerator opening Acc from the accelerator position sensor 74, signals from various sensors necessary for controlling the operation of the motors MG1 and MG2, such as the rotational positions θm1 and θm2 of the motors MG1 and MG2 from the rotational position sensor, and signals from various sensors necessary for managing the battery 50. The ECU 70 outputs various control signals for controlling the operation of the engine 22 and control signals to the inverters 41 and 42.

The hybrid vehicle 20 thus configured basically runs in a hybrid running (HV running) mode in which the engine 22 is running, or in an electric running (EV running) mode in which the engine 22 is stopped, under the control of the ECU 70. For example, in the HV running mode, the required torque Td* corresponding to the accelerator opening Acc and the vehicle speed V is set from a map showing the relationship between the accelerator opening Acc, the vehicle speed V, and the required torque Td* required for the drive shaft 36, and the target rotation speed Ne* and target torque Te* of the engine 22 and the torque commands Tm1* and Tm2* of the motors MG1 and MG2 are set so that the required torque Td* is output to the drive shaft 36, and the engine 22 is operated based on the target rotation speed Ne* and the target torque Te*, and the inverters 41 and 42 are controlled so that the motors MG1 and MG2 are driven with the torque commands Tm1* and Tm2*.

Although not shown, the data storage server 80 is equipped with a microcomputer having a CPU, ROM, RAM, flash memory, input/output ports, and communication ports. The data storage server 80 receives various data from the hybrid vehicle 20 via communication and stores the received data in the flash memory.

Although not shown, the replacement determination server 82 is equipped with a microcomputer having a CPU, ROM, RAM, flash memory, input/output ports, and communication ports. The replacement determination server 82 receives various data from the data accumulation server 80 via communication, and determines whether or not the lubricating oil should be replaced based on the received data. The determination of whether or not to replace the lubricating oil will be described later.

The dealer server 84 is installed in the dealer that sold the hybrid vehicle 20, and although not shown, is equipped with a microcomputer having a CPU, ROM, RAM, flash memory, input/output ports, and communication ports. The dealer server 84 receives various information from the exchange determination server 82 via communication.

Next, the operation of the oil life determination system 10 of the embodiment thus configured will be described. The data accumulation server 80 receives the vehicle speed V detected by the vehicle speed sensor 72 and the accelerator opening Acc detected by the accelerator position sensor 74 from the hybrid vehicle 20 via communication at every predetermined time tref1 (for example, every 60 seconds), and accumulates the received vehicle speed V and accelerator opening Acc for every predetermined time tref1 in a flash memory as time-series vehicle speed data V(1) to V(n) and accelerator opening data Acc(1) to Acc(n) (n is an integer of 2 or more). The time-series vehicle speed data V(1) to V(n) and accelerator opening data Acc(1) to Acc(n) accumulated by the data accumulation server 80 are accumulated in the flash memory of the data accumulation server 80 without being erased until a data reset is requested.

Figure 2 is a flowchart showing an example of an exchange determination routine executed by the exchange determination server 82. This routine is executed repeatedly at a predetermined time interval tref2 (e.g., every two days).

When this routine is executed, the CPU of the exchange determination server 82 executes a process of receiving the vehicle speed data V(1) to V(n) and accelerator opening data Acc(1) to Acc(n) stored in the data storage server 80 (step S100). Next, the received data is pre-processed (step S110). In the pre-processing, first, all the received data is arranged in chronological order. Next, any data that falls outside a predetermined range is replaced with the data immediately before it. Also, if there is missing data when the received data is arranged in chronological order, the missing data is linearly interpolated using the data before and after the missing data. In the following explanation of steps S120 to S180, the vehicle speed data V(1) to V(n) and accelerator opening data Acc(1) to Acc(n) after pre-processing are referred to as "vehicle speed data V(1) to V(n)" and "accelerator opening data Acc(1) to Acc(n)".

Next, the rotation speed data Nd(1) to Nd(n) is calculated as time series data of the rotation speed Nd of the drive shaft 36 based on each of the vehicle speed data V(1) to V(n), the radius rw of the drive wheels 39a, 39b, and the gear ratio Gdiff of the differential gear 38 (step S120).

Next, using the same method as for setting the required torque Td* in the control in the HV driving mode, the required torque data Td(1)-Td(n) is set as time-series data of the required torque Td* based on each of the vehicle speed data V(1)-V(n) and the accelerator opening data Acc(1)-Acc(n) corresponding to each of the vehicle speed data V(1)-V(n) (step S130).

Next, the deterioration parameter Pdg indicating the degree of deterioration of the lubricating oil is calculated by the following formula (1) using the required torque data Td(1) to Td(n) and the rotation speed data Nd(1) to Nd(n) (step S140). In formula (1), "F(Td(n))" is a weighting function greater than 0 and less than or equal to 1, and is set to be larger when the required torque data Td(n) is large than when it is small, and is set to be larger when the required torque data Td(n) is equal to or greater than a predetermined value than when it is less than the predetermined value. The indexes "m1" and "m2" are set to a value of 1 or more for each type of lubricating oil based on the properties of the lubricating oil. In general, when the gears of the gear mechanism slip while being subjected to a large load due to the torque of the rotating shaft, the degree of deterioration of the lubricating oil increases. It is considered that the degree of deterioration of such lubricating oil is greater when the torque and rotation speed of the rotating shaft are large than when they are small. The first term of formula (1) is larger when the required torque data Td(n) or the rotation speed data Nd(n) is large than when they are small, and therefore indicates the degree of deterioration of the lubricating oil caused by the differential gear 38 slipping under a large load due to the torque of the drive shaft 36. In addition, the degree of deterioration increases when the rotation speed of the gear immersed in the lubricating oil of the gear mechanism is high and the lubricating oil is vigorously stirred. It is considered that the degree of deterioration of such lubricating oil is larger when the rotation speed of the rotating shaft is high than when it is low. The second term of formula (1) is larger when the rotation speed data Nd(n) is large than when it is low, and therefore indicates the degree of deterioration of the lubricating oil caused by the high rotation speed of the differential gear 38 and the vigorously stirred lubricating oil. Therefore, the deterioration parameter Pdg is a parameter that indicates the degree of deterioration of the lubricating oil. The calculation of the deterioration parameter Pdg requires only two types of information: the required torque data Td(n) and the rotation speed data Nd(n). The required torque data Td(n) and the rotation speed data Nd(n) are necessary information for running the hybrid vehicle 20, and can be obtained without adding a sensor to calculate the deterioration parameter Pdg. Therefore, the deterioration parameter Pdg of the lubricating oil can be calculated while suppressing an increase in the number of parts.

Once the deterioration parameter Pdg has been calculated in this manner, the lubricating oil's kinetic viscosity estimate (kinetic viscosity estimate) Kvest is calculated (step S150) using the following formula (2) or (3). Figure 3 is an explanatory diagram showing an example of the relationship between the deterioration parameter Pdg and the kinetic viscosity estimate Kvest. Formulas (2) and (3) are formulas that represent the relationship illustrated in Figure 3. In formulas (2) and (3), "e", "f", "g", "h", "i", and "Pdref" can be determined from the relationship in Figure 3.

Next, the current travel distance Lnow is calculated by multiplying each of the vehicle speed data V(1) to V(n) by a predetermined time tref1, which is the time interval at which the data accumulation server 80 inputs the vehicle speed V from the hybrid vehicle 20 via communication (step S160).

Then, it is determined whether or not at least one of the following is true: the estimated kinetic viscosity value Kvest is smaller than the threshold value Kvth, or the travel distance Lnow is greater than the threshold value Lth (step S170). The threshold value Kvth is a value determined in advance through experiments, analysis, etc. as the minimum value of kinetic viscosity guaranteed when using the lubricating oil. The threshold value Lth is a distance guaranteed in the usage environment against oxidation deterioration of the lubricating oil, and is a value determined in advance through experiments, analysis, etc. Therefore, step S170 is a process of determining whether the lubricating oil has deteriorated and should be replaced.

If in step S170 the estimated kinetic viscosity value Kvest is equal to or greater than the threshold value Kvth and the traveled distance Lnow is equal to or less than the threshold value Lth, it is determined that there is no need to change the lubricating oil, and this routine is terminated.

If at least one of the following is true in step S170: the estimated kinetic viscosity value Kvest is smaller than the threshold value Kvth, or the mileage Lnow is greater than the threshold value Lth, it is determined that the lubricating oil should be changed, and the dealer server 84 is notified that the oil should be changed (step S180), and this routine ends. When the dealer server 84 receives the notification that the oil should be changed, it prompts the dealer staff to change the oil by displaying the fact that the oil change is necessary on a display (not shown) or by notifying the dealer staff when the hybrid vehicle 20 is brought into stock.

According to the oil life determination system 10 equipped with the deterioration parameter calculation system of the embodiment described above, the deterioration parameter Pdg of the lubricating oil can be calculated while suppressing an increase in the number of parts by calculating the deterioration parameter Pdg based on the required torque data Td(n) and the rotation speed data Nd(n).

In the oil life determination system 10 equipped with the deterioration parameter calculation system of the embodiment, in steps S170 and S180, it is determined whether or not at least one of the following is true: the kinetic viscosity estimated value Kvest is smaller than the threshold value Kvth, or the mileage Lnow is greater than the threshold value Lth, and the dealer server 84 is notified of an oil change. However, instead of S170 and S180, the remaining distance Lr1, which is the distance from the current position until the kinetic viscosity estimated value Kvest falls below the threshold value Kvth, and the remaining distance Lr2, which is the distance from the current position until the mileage Lnow exceeds the threshold value Lth, may be calculated, and the shorter of the remaining distances Lr1 and Lr2 may be notified to the dealer server 84 as the remaining distance until the oil change. Here, the remaining distance Lr1 is the distance obtained by subtracting the mileage Lnow from the mileage Lkv at which the kinetic viscosity estimated value Kvest becomes the threshold value Kvth. The mileage Lkv can be calculated by substituting the threshold value Kvth for the estimated kinetic viscosity value Kvest and the degradation parameter Pdgkv for the degradation parameter Pdg in the above formula (3) into formula (4), which is transformed to obtain the degradation parameter Pdgkv, and multiplying the ratio of the degradation parameter Pdgkv to the current degradation parameter Pdg by the current mileage Lnow using the following formula (5). The remaining distance Lr2 is the value obtained by subtracting the mileage Lnow from the threshold value Lth. In this way, the dealer staff can be informed of the distance the hybrid vehicle 20 can travel before an oil change is required.

In the oil life determination system 10 equipped with the deterioration parameter calculation system of the embodiment, the data accumulation server 80 accumulates data on the vehicle speed V and accelerator opening Acc, but accumulation of the data on the vehicle speed V and accelerator opening Acc is not limited to the data accumulation server 80, and may be performed by the hybrid vehicle 20, the replacement determination server 82, or the dealer server 48.

In the oil life determination system 10 equipped with the deterioration parameter calculation system of the embodiment, at least a part of the replacement determination routine illustrated in FIG. 2 may be performed by the hybrid vehicle 20, the data accumulation server 80, or the dealer server 84.

In the embodiment, the degradation parameter calculation system of the present invention is applied to a hybrid vehicle 20. However, the present invention may be applied to any vehicle that has at least one gear, is connected to a rotating shaft, is lubricated by lubricating oil, and has a gear mechanism in which the lubricating oil is stirred by the gear as the gear rotates. For example, the present invention may be applied to a vehicle that does not have a motor for running but has an engine and a transmission as a gear mechanism, or may be applied to a machine tool or durability bench that has such a gear mechanism.

The above describes the form for carrying out the present invention using examples, but the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be carried out in various forms without departing from the spirit of the present invention.

10 Oil life determination system, 20 Hybrid vehicle, 82 Replacement determination server.

Claims (1)

A deterioration parameter calculation system for calculating a deterioration parameter indicating a degree of deterioration of lubricating oil that lubricates a gear mechanism having at least one gear and is connected to a rotating shaft and is stirred by the gear as the gear rotates, comprising:
A deterioration parameter calculation system that calculates the deterioration parameter based on a torque of the rotating shaft and a rotation speed of the rotating shaft.

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