Engine oil degradation detection device

Abstract

To improve the accuracy of engine oil degradation detection. [Solution] An engine oil degradation determination device for an internal combustion engine configured to utilize at least two types of fuel, wherein for each type, data relating the engine coolant temperature and the cumulative consumption of that type at that engine coolant temperature constitutes cumulative consumption data, and for each type, the device uses the cumulative consumption data of that type to calculate the amount of engine oil degradation at that engine coolant temperature based on the cumulative consumption at each engine coolant temperature and the degradation rate of engine oil per unit consumption at that engine coolant temperature.

Description

Technical Field

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[0001] The present invention relates to an engine oil deterioration determination device.

Background Art

[0002] An example of an engine oil deterioration determination device calculates the replacement timing of engine oil in a diesel engine vehicle using biodiesel fuel. The calculation of the replacement timing of engine oil specifies a correction coefficient based on the biodiesel fuel concentration. Then, when the corrected value obtained by multiplying the driving distance by the correction coefficient is greater than or equal to a certain value, the engine oil deterioration determination device determines that the state of the engine oil has reached the replacement timing (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The determination of specifying the correction coefficient based on the biodiesel fuel concentration assumes that the deterioration rate of engine oil due to biodiesel fuel has a certain ratio compared to normal diesel fuel regardless of the operating state of the engine.

[0005] On the other hand, the factors causing engine oil deterioration include an increase in insoluble components in the engine oil and oxidation of the engine oil. When the fuel of a gasoline engine vehicle contains bioethanol, since bioethanol does not contain unsaturated hydrocarbons, the contribution of insoluble components is reduced, but the contribution of engine oil oxidation still remains. As a result, in a determination that does not distinguish different deterioration factors such as specifying a correction coefficient based on fuel concentration or multiplying the driving distance by the correction coefficient, the accuracy of engine oil deterioration determination is lacking.

[0006] Furthermore, because the state of fuel combustion changes depending on the combustion chamber wall temperature, even if the engine oil has traveled the same distance, differences in the amount of unburned fuel will cause the engine oil to deteriorate at different rates. For this reason, a correction that keeps the correction coefficient constant regardless of driving conditions will further reduce the accuracy of engine oil deterioration assessment. [Means for solving the problem]

[0007] An engine oil degradation determination device that solves the above problems is an engine oil degradation determination device for an internal combustion engine configured to be able to use at least two types of fuel, wherein for each type, data relating the engine coolant temperature and the cumulative consumption amount of that type consumed at that engine coolant temperature is called cumulative consumption data, and for each type, the device uses the cumulative consumption data of that type to calculate the amount of engine oil degradation at that engine coolant temperature by that type, based on the cumulative consumption amount for each engine coolant temperature and the degradation rate of the engine oil per unit consumption at that engine coolant temperature. [Effects of the Invention]

[0008] This engine oil degradation detection device can reflect differences in fuel type and operating conditions in the amount of engine oil degradation used for engine oil degradation detection. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a diagram showing the configuration of an internal combustion engine to which an engine oil degradation detection device is applied. [Figure 2] Figure 2 is a diagram showing the cumulative consumption data. [Figure 3] Figure 3 is a flowchart showing the method for determining engine oil quality. [Modes for carrying out the invention]

[0010] The following describes an embodiment of an internal combustion engine to which an engine oil degradation detection device is applied, with reference to the drawings. Engine 10 is an on-board engine configured to use an alcohol-blended fuel, which is a mixture of gasoline and alcohol, as fuel. In the following description, the alcohol-blended fuel will be simply referred to as fuel.

[0011] As shown in Figure 1, the engine 10 comprises a cylinder 12 in which a piston 11 is arranged to reciprocate, and an injector 13 that injects fuel into the cylinder 12. The cylinder 12 is connected to an intake passage 15 via an intake valve 14. The cylinder 12 is connected to an exhaust passage 17 via an exhaust valve 16. The piston 11 partitions a combustion chamber 18 within the cylinder 12. The combustion chamber 18 generates a mixture of intake air introduced through the intake passage 15 and fuel injected from the injector 13. The ignition device 19 ignites the mixture in the combustion chamber 18 by spark discharge. The throttle valve 21 adjusts the intake airflow rate. The engine 10 includes a variable valve timing mechanism 22 that makes the valve timing of the intake valve 14 variable.

[0012] The engine 10 is controlled by an engine control module (ECM40). The ECM40 includes a memory 41 that stores control programs and data, and an arithmetic processing circuit 42 that executes the programs read from the memory 41. The ECM40 performs engine oil degradation detection as part of driving control and vehicle control. The ECM40 is an example of an engine oil degradation detection device.

[0013] The arithmetic processing circuit 42 calculates the operating status and driving status of the engine 10 using input signals from various sensors. The various sensors include an air flow meter 20, an air-fuel ratio sensor 25, a crank angle sensor 26, and a water temperature sensor 28. The air flow meter 20 detects the intake airflow rate in the intake passage 15. The air-fuel ratio sensor 25 detects the air-fuel ratio in the exhaust passage 17. The crank angle sensor 26 detects the rotation angle of the crankshaft 27.

[0014] The arithmetic processing circuit 42 detects the engine coolant temperature, which is the temperature of the coolant in the engine 10, when determining the deterioration of the engine oil. The engine coolant temperature will also be referred to as the coolant temperature below. When determining the deterioration of the engine oil, the arithmetic processing circuit 42 may detect the engine oil temperature instead of the coolant temperature, or it may detect the temperature of the outer circumference of the combustion chamber 18. In this case, the engine 10 is equipped with an oil temperature sensor for detecting the engine oil temperature, and the arithmetic processing circuit 42 may use the engine oil temperature input from the oil temperature sensor. Alternatively, the engine 10 is equipped with a temperature sensor for detecting the temperature of the outer circumference of the combustion chamber 18, and the arithmetic processing circuit 42 may use the temperature of the outer circumference input from the temperature sensor.

[0015] The arithmetic processing circuit 42 estimates the alcohol concentration in the fuel when determining the deterioration of the engine oil. The arithmetic processing circuit 42 may use the intake airflow rate input from the airflow meter 20, the fuel injection amount injected by the injector 13, and the air-fuel ratio input from the air-fuel ratio sensor 25 to estimate the alcohol concentration. Alternatively, the arithmetic processing circuit 42 may measure the alcohol concentration in the fuel instead of estimating the alcohol concentration when determining the deterioration of the engine oil. In this case, the engine 10 is equipped with an alcohol concentration sensor in the fuel tank or fuel transport path to detect the alcohol concentration of the fuel, and the arithmetic processing circuit 42 uses the alcohol concentration input from the alcohol concentration sensor to determine the deterioration of the engine oil.

[0016] The arithmetic processing circuit 42 repeatedly calculates the instantaneous value of fuel consumption when determining engine oil degradation. The arithmetic processing circuit 42 causes the engine 10 to perform various operations to improve operating performance and fuel efficiency. The arithmetic processing circuit 42 applies the current operating point of the engine 10 to the fuel efficiency map for each type of operation and calculates the current instantaneous value of fuel consumption.

[0017] The arithmetic processing circuit 42 may, for example, perform various operations such as cylinder deactivation operation or all-cylinder operation. In all-cylinder operation, the arithmetic processing circuit 42 may apply the current operating point to the fuel consumption map related to all-cylinder operation to calculate the instantaneous value of the current fuel consumption. In cylinder deactivation operation, the arithmetic processing circuit 42 may apply the current operating point to the fuel consumption map related to cylinder deactivation operation to calculate the instantaneous value of the current fuel consumption. The fuel consumption map may show a set of operating points where the fuel consumption is equal, with engine rotation speed and engine torque as operating points. The arithmetic processing circuit 42 calculates the engine rotation speed, which is the rotation speed of the crankshaft 27, using the rotation angle input by the crank angle sensor 26. The arithmetic processing circuit 42 calculates the engine torque using the intake air flow rate input by the air flow meter 20 and the engine rotation speed. The arithmetic processing circuit 42 may apply the engine rotation speed and engine torque to the fuel consumption map to calculate the instantaneous value of the current fuel consumption.

[0018] The engine 10 may also be equipped with a flow sensor that detects the fuel flow rate supplied from the fuel tank, and the calculation processing circuit 42 may calculate an instantaneous value of fuel consumption using the input signal from the flow sensor.

[0019] As shown in Figure 2, memory 41 stores cumulative consumption data 53. Memory 41 stores cumulative consumption data 53 at the time of engine oil change and the latest cumulative consumption data 53. The cumulative consumption data 53 is stored separately for each type of fuel that makes up the alcohol-blended fuel, such as gasoline or alcohol.

[0020] The integrated consumption data 53 includes the integrated consumption by temperature for each type of fuel. The integrated consumption data 53 includes the deterioration rate by temperature when the concentration of each type of fuel is 100%. For the type of fuel associated with the integrated consumption data 53, the integrated consumption and the deterioration rate in each separate range of coolant temperature are associated with each other within the range. The integrated consumption in each separate range of coolant temperature is the integrated value of the instantaneous value of the consumption of the fuel of that type within that range. The deterioration rate in each separate range of coolant temperature is the deterioration rate within that range for an alcohol blended fuel when the concentration of the fuel of that type is 100%.

[0021] In the example of the integrated consumption data 53 shown in FIG. 2, for a predetermined type of fuel, an integrated consumption A1 and a deterioration rate E1 are associated with a temperature T1 or higher and lower than temperature T2. Also, an integrated consumption A2 and a deterioration rate E2 are associated with a temperature T2 or higher and lower than temperature T3. Also, an integrated consumption A3 and a deterioration rate E3 are associated with a temperature T3 or higher and lower than temperature T4. Also, an integrated consumption A4 and a deterioration rate E4 are associated with a temperature T4 or higher and temperature T5.

[0022] The ECM 40 includes obtaining the coolant temperature, obtaining the alcohol concentration, calculating the instantaneous value of the fuel consumption, and updating the integrated consumption data 53 for determining the deterioration of the engine oil. The ECM 40 calculates the instantaneous value of the fuel consumption for each type of fuel using the instantaneous value of the fuel consumption and the alcohol concentration. The ECM 40 updates the integrated consumption data 53 corresponding to that type using the instantaneous value of the fuel consumption for each type of fuel and the coolant temperature. That is, the ECM 40 adds the instantaneous value of the fuel consumption of that type to the integrated consumption associated with the range corresponding to that coolant temperature using the instantaneous value of the fuel consumption for each type of fuel and the coolant temperature. Thereby, the ECM 40 distributes the integrated fuel consumption for each type of fuel according to the range of the coolant temperature.

[0023] As shown in FIG. 3, the ECM 40 includes obtaining the integrated consumption at the time of replacement, obtaining the latest integrated consumption, and calculating the consumption amount for determining the deterioration of the engine oil. Further, the ECM 40 includes calculating the deterioration amount and calculating the remaining life for determining the deterioration of the engine oil.

[0024] That is, in determining the deterioration of the engine oil, the ECM 40 first obtains the latest integrated consumption data 53 at the time of replacing the engine oil, and stores the latest integrated consumption data 53 in the memory 41 as the integrated consumption data 53 at the time of replacement (step S11). Next, after replacing the engine oil, the ECM 40 repeatedly updates the latest integrated consumption data 53 (step S12).

[0025] Next, the ECM 40 calculates the difference in the integrated consumption for each range of the coolant temperature for each type of fuel using the integrated consumption data 53 at the time of replacement and the latest integrated consumption data 53 (step S13). That is, the ECM 40 calculates the integrated value of the fuel consumption consumed after replacing the engine oil for each range of the coolant temperature for each type of fuel. Next, the ECM 40 multiplies the integrated value of the fuel consumption after replacement by the deterioration rate in the range for each range of the coolant temperature for each type of fuel to calculate the deterioration amount in the range. Further, the ECM 40 calculates the deterioration amount of the engine oil by summing the deterioration amounts for each range of the coolant temperature in all types (step S14). Then, the ECM 40 estimates the remaining life of the engine oil using the deterioration amount of the engine oil (step S15). The ECM 40 may estimate the remaining life of the engine oil using the deterioration amount of the engine oil, the mileage after replacing the engine oil, and the number of days of use of the engine oil. Note that the ECM 40 may determine whether the deterioration amount of the engine oil reaches a predetermined value.

[0026] <Operations and Effects of the Present Embodiment> (1) The amount of engine oil degradation is the sum of the degradation amounts for each type of fuel. The amount of degradation for each type of fuel is calculated using the cumulative value of fuel consumption for each coolant temperature range for that type and the degradation rate for each type within that coolant temperature range. Therefore, degradation factors such as insoluble matter and oxidation, which differ for each type of fuel, are distinguished in the calculation of the amount of engine oil degradation. As a result, the accuracy of engine oil degradation assessment is improved.

[0027] (2) Furthermore, changes in the amount of unburned fuel due to changes in the wall temperature of the combustion chamber 18 change the rate of deterioration of the engine oil. In this regard, the calculation of the amount of engine oil deterioration uses the deterioration rate for each type of fuel and each range of coolant temperature. Therefore, deterioration factors that differ depending on the operating conditions of the engine 10 are distinguished in the calculation of the amount of engine oil deterioration. As a result, the accuracy of engine oil deterioration determination is improved.

[0028] (3) The ECM40 calculates the amount of engine oil degradation as part of the driving control and traction control. Therefore, the amount of engine oil degradation is obtained based on the latest cumulative consumption data53.

[0029] <Example of changes> The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0030] The vehicle data storage server may manage the cumulative consumption data 53 at the time of replacement. For example, the engine oil degradation detection device comprises an ECM 40 and a communication device mounted on the vehicle, and is configured to communicate with a vehicle data storage server. The vehicle data storage server sends a transmission request to the communication device when an event such as an engine oil change occurs. The engine oil degradation detection device receives the transmission request from the vehicle data storage server and sends cumulative consumption data 53 to the vehicle data storage server. The engine oil degradation detection device sends a transmission request to the vehicle data storage server when the mileage since the last oil change exceeds a predetermined distance or when a request for degradation detection is received from an external source. The vehicle data storage server stores the cumulative consumption data 53 at the time of change and, upon receiving the transmission request from the engine oil degradation detection device, transmits the cumulative consumption data 53 at the time of change.

[0031] The engine oil degradation determination device may consist of a vehicle data storage server, and the vehicle data storage server may calculate the amount of engine oil degradation. For example, the vehicle data storage server sends a transmission request to the ECM40 during its processing cycle. The ECM40 receives the transmission request from the vehicle data storage server and sends instantaneous values ​​of coolant temperature, alcohol concentration, and fuel consumption to the vehicle data storage server. The vehicle data storage server then distributes the cumulative fuel consumption for each type of fuel and for each range of coolant temperature. The vehicle data storage server then executes the processes from steps S11 to S15 described above. The vehicle data storage server receives transmission requests from external terminals such as communication devices and mobile terminals connected to the ECM40 and sends the calculated degradation amount and remaining lifespan to the communication devices and external terminals.

[0032] The cumulative consumption data 53 may associate the cumulative consumption with the engine oil temperature instead of the coolant temperature, or with the temperature around the combustion chamber 18. The ECM 40 may then distribute the cumulative consumption according to the range of engine oil temperatures for each type of fuel, or according to the range of temperatures around the combustion chamber 18.

[0033] The engine oil degradation determination device may use indicators other than the two indicators of engine oil type and coolant temperature to determine degradation. In step S15 above, the engine oil degradation determination device may calculate the remaining lifespan of the engine oil using the degradation amount that represents the most advanced degradation of the engine oil among the degradation amount calculated using the cumulative consumption data 53 and the degradation amount using the other indicator. [Explanation of Symbols]

[0034] 10...Internal combustion engine, 11...Piston, 12...Cylinder, 13...Injector, 14...Intake valve, 15...Intake passage, 16...Exhaust valve, 17...Exhaust passage, 18...Combustion chamber, 19...Ignition system, 20...Airflow meter, 21...Throttle valve, 40...ECM, 41...Memory, 42...Calculation circuit, 53...Cumulative consumption data.

Claims

[Claim 1] A device for determining the deterioration of engine oil in an internal combustion engine configured to utilize at least two types of fuel, For each of the aforementioned types, the cumulative consumption data is data that associates the engine coolant temperature with the cumulative consumption of that type at that engine coolant temperature. For each of the aforementioned types, the amount of engine oil degradation at that engine coolant temperature is calculated based on the cumulative consumption data for that type, the cumulative consumption for each engine coolant temperature, and the degradation rate of the engine oil per unit consumption at that engine coolant temperature. An engine oil degradation detection device characterized by the following:

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