JP2008297912A - Lubricating oil quantity estimation device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricating oil quantity estimation device of an internal combustion engine capable of estimating the quantity of lubricating oil remaining in the internal combustion engine even in such a case that a level sensor for detecting the lubricating oil of the internal combustion engine is not equipped. <P>SOLUTION: In the internal combustion engine mounted on a vehicle, a DPF (diesel particular filter) for collecting PM (particulate matter) discharged from the internal combustion engine is provided in an exhaust passage. In the DPF, ash generated as the lubricating oil of the internal combustion engine is burnt is also collected. The electronic control device of the vehicle derives a differential pressure ΔP of an upstream side and a downstream side of the DPF corresponding to the quantity of the ash accumulated in the DPF and judges whether the differential pressure ΔP rises a predetermined pressure Δps or more from the time when the lubricating oil is replaced and thus estimates that the quantity of the lubricating oil remaining in the internal combustion engine is reduced to a predetermined quantity W (S12) and a replacement timing of the lubricating oil is informed (S13). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lubricating oil amount estimation device that estimates the amount of lubricating oil in an internal combustion engine.

  Conventionally, in an internal combustion engine, lubricating oil is supplied to the sliding portions in order to reduce the frictional resistance at each sliding portion. This lubricating oil is stored in an oil pan disposed under the cylinder block in the internal combustion engine, and is supplied to each sliding portion via an oil pump that is driven together with the driving of the internal combustion engine. The lubricating oil used for lubricating the piston and the cylinder during operation of the internal combustion engine may leak into the combustion chamber, and the lubricating oil leaked into the combustion chamber together with the fuel in the combustion stroke of the internal combustion engine. When combusted, the lubricating oil is discharged out of the vehicle together with the exhaust gas, so this lubricating oil gradually decreases. When the amount of the lubricating oil is reduced in this way, it becomes impossible to achieve lubrication of each sliding portion with the above-described lubricating oil. Therefore, the internal combustion engine is usually provided with a pressure sensor that detects the discharge pressure of the lubricating oil discharged from the oil pump. In the internal combustion engine, when the discharge pressure detected by the pressure sensor becomes a predetermined value or less. It is determined that the lubricating oil has decreased to a predetermined amount that needs to be replaced, and the user is notified of the replacement timing of the lubricating oil. When the time for replacing the lubricating oil based on the discharge pressure of the oil pump is notified as described above, the lubricating oil is often reduced to a state where the lubricating oil must be replaced. Therefore, for example, an internal combustion engine is provided in which a level sensor for measuring the amount of lubricating oil stored in an oil pan is provided so that the user can be notified of the amount of stored lubricating oil.

Further, for example, Patent Literature 1 describes an oil maintenance instruction device that informs a user of a replacement time of a lubricating oil according to the degree of deterioration of the lubricating oil. This indicating device is applied to, for example, an internal combustion engine such as a diesel engine and provided with a DPF (diesel particulate filter) for collecting PM (particulate matter) in an exhaust passage thereof. Specifically, this oil maintenance instruction device performs regeneration by judging the regeneration timing of PM based on the differential pressure of the DPF, and derives the total combustion amount of PM combusted by this regeneration. If the amount of combustion is greater than or equal to a predetermined amount, the user is notified of the replacement of the lubricating oil because the lubricating oil has deteriorated.
JP 2005-307873 A

  By the way, as described above, when the replacement time of the lubricating oil is notified based on the discharge pressure of the oil pump detected by the pressure sensor, it is already in a situation where it is necessary to replace the lubricating oil. In many cases, for example, when the lubricating oil is not replaced immediately after such notification is given, there is a possibility that the respective parts of the internal combustion engine cannot be properly lubricated. Therefore, it is preferable to notify the user of the amount of the lubricating oil remaining in the internal combustion engine before the replacement of the lubricating oil becomes imminent, and prompt the user to replace the lubricating oil. In this regard, as described above, by providing a lubricating oil level sensor in the oil pan, it is possible to notify the user of the amount of lubricating oil and the replacement time early, but in this case, the amount of lubricating oil is reduced. A dedicated sensor for detection is required.

  Note that the oil maintenance instruction device described in Patent Document 1 notifies the replacement of the lubricating oil by the total combustion amount of the PM, and the total combustion amount of the PM does not necessarily reflect the reduction amount of the lubricating oil. Therefore, the amount of lubricating oil remaining in the internal combustion engine cannot be estimated. Therefore, even when the apparatus described in Patent Document 1 is used, if the lubricating oil level sensor is not provided in the oil pan, the amount of remaining lubricating oil is determined based on the discharge pressure of the oil pump. Thus, the notification of the replacement timing of the lubricating oil based on the decrease in the lubricating oil is performed at a timing at which the lubricating oil must actually be replaced.

  The present invention has been made in view of such circumstances, and its purpose is to determine the amount of lubricating oil remaining in the internal combustion engine even when a level sensor for detecting the lubricating oil of the internal combustion engine is not provided. An object of the present invention is to provide a lubricating oil amount estimation device for an internal combustion engine that can be estimated.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
The invention according to claim 1 is a filter that is disposed in an exhaust passage of an internal combustion engine and collects particulate matter discharged from the engine, and an ash amount deriving unit that derives the amount of ash accumulated on the filter. And a lubricating oil amount estimating means for estimating the amount of lubricating oil remaining in the engine based on the ash amount derived by the ash amount deriving means.

  In the above configuration, the filter for collecting the particulate matter has ash (non-combustible component contained in the lubricant) generated by burning the lubricant leaked into the combustion chamber together with the particulate matter. It is collected. And in said structure, since the quantity of lubricating oil consumed by combustion is derived | led-out by deriving the amount of ash deposited on the filter by the ash quantity deriving means, it remains in the internal combustion engine based on this. The amount of lubricating oil is estimated. Here, since the incombustible component in the lubricating oil to be ash is contained in the lubricating oil at a predetermined concentration, the amount of accumulated ash reflects the amount of lubricating oil consumed by combustion. In this way, according to the above configuration, the amount of lubricating oil remaining in the internal combustion engine can be estimated without providing a lubricating oil level sensor or the like.

  Specifically, according to the second aspect of the present invention, there is provided differential pressure detecting means for detecting a differential pressure between the upstream side and the downstream side of the filter, and the ash amount deriving means is configured to detect the differential pressure. A mode in which the amount of the ash is derived based on the differential pressure of the filter detected by the means can be employed.

  The invention according to claim 3 is the invention according to claim 1 or 2, further comprising regeneration means for regenerating the filter by burning the particulate matter collected by the filter, The gist of the deriving means is to derive the amount of the ash deposited on the filter immediately after the filter is regenerated by the regenerating means.

  In the above configuration, when the filter is regenerated by the regenerating means, the particulate matter deposited on the filter is removed, and only the ash is substantially accumulated on the filter. Therefore, according to the above configuration, the amount of ash deposited on the filter can be derived without being affected by the particulate matter collected by the filter. Thus, according to the above configuration, the amount of ash accumulated on the filter can be accurately derived, so that the amount of lubricating oil remaining in the internal combustion engine can be accurately estimated based on this. .

  According to a fourth aspect of the present invention, in the invention according to the third aspect, the ash amount deriving means has a minimum amount of particulate matter remaining in the filter during regeneration of the filter performed by the regenerating means. The gist of the present invention is to derive the amount of the ash accumulated on the filter.

  Even when the filter is regenerated by the regenerating means, the particulate matter may remain on the filter depending on the regenerating conditions. In this regard, according to the above configuration, in such a case, for example, the regeneration of the filter is performed again so that the amount of ash is derived when the minimum amount of particulate matter remaining in the filter is reached. Therefore, even if the filter is not completely regenerated every time, the amount of ash deposited on the filter can be accurately derived. The amount of lubricating oil can be estimated more accurately based on the amount of ash thus accurately derived.

  According to a fifth aspect of the present invention, in the first or second aspect of the invention, the ash amount deriving means includes: a total deposit amount deposited on the filter; a deposit amount of the particulate matter; And the amount of the ash is derived based on the accumulated amount of the total deposit and the accumulated amount of the particulate matter.

  In the above configuration, ash is deposited together with particulate matter on the filter. Therefore, according to the above configuration, the deposition amount of the particulate matter is derived from the deposition amount of the total deposit deposited on the filter and the deposition amount of the particulate matter. Is subtracted, the amount of ash deposited on the filter can be derived. Note that the total amount of deposits deposited on the filter is, for example, according to the invention of claim 2, rather than deriving the amount of ash and the amount of particulate matter in the deposits, respectively. It can be easily derived by calculating the differential pressure between the upstream side and the downstream side of the filter. The amount of particulate matter deposited on the filter can be derived based on, for example, the operating conditions of the internal combustion engine. Thus, according to the above configuration, the amount of ash can be derived not only immediately after regeneration of the filter, but the amount of lubricating oil remaining in the internal combustion engine can be estimated at any time.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the lubricating oil amount estimating means is configured such that when the amount of ash accumulated on the filter reaches a predetermined accumulation amount, the engine It is estimated that the amount of the lubricating oil remaining in the tank is reduced to a predetermined amount, and the replacement timing of the lubricating oil is notified.

  According to the above configuration, since the lubricating oil amount estimating means can notify the user of the replacement time of the lubricating oil, if the predetermined amount of the lubricating oil amount is appropriately set, the lubricating oil can be replaced appropriately. Thus, lubrication of the sliding portion of the internal combustion engine can be performed appropriately.

  According to a seventh aspect of the present invention, in the invention according to any one of the first to sixth aspects, the lubricating oil amount estimating means is deposited on the filter when the lubricating oil is replaced. When the ash amount derived by the ash amount deriving means is increased by a predetermined accumulation amount with respect to the ash amount as a reference amount, the amount of the lubricating oil remaining in the internal combustion engine is determined. The gist is to estimate that the amount has been reduced to quantitative.

  According to the above configuration, every time the lubricating oil is replaced, the amount of the lubricating oil is estimated based on the amount of ash accumulated on the filter when the replacement is performed. Even when the operation is performed, the amount of the lubricating oil remaining in the internal combustion engine can be appropriately estimated each time.

(First embodiment)
Hereinafter, with reference to FIGS. 1 to 4, a first embodiment in which a lubricating oil amount estimating device for an internal combustion engine according to the present invention is embodied will be described.

  FIG. 1 is a schematic diagram of an in-vehicle internal combustion engine to which a lubricating oil amount estimation device according to the present invention is applied. In the internal combustion engine 10, the combustion chamber 12 is defined by the cylinder 11 and the piston 24 in each cylinder 11 formed in the cylinder block. A crankcase 21 is formed below each cylinder 11, and an oil pan 29 is attached to the lower portion of the crankcase 21. The oil pan 29 stores lubricating oil used for lubricating a sliding portion between the piston 24 and the cylinder 11 and a rotating portion such as the crankshaft 23. The lubricating oil in the oil pan 29 is supplied to these sliding portions via an oil pump (not shown). Further, the internal combustion engine 10 includes an intake passage 13 for sending intake air to the combustion chamber 12 and an exhaust passage 14 for exhausting exhaust gas generated by combustion in the combustion chamber 12. In the internal combustion engine 10, the intake passage 13 and the combustion chamber 12 are connected and cut off by the opening / closing operation of the intake valve 18, and the exhaust passage 14 and the combustion chamber 12 are connected and cut off by the opening / closing operation of the exhaust valve 19. The

  The intake passage 13 is provided with an intake throttle valve 15 whose passage area is variable, and the intake throttle valve 15 is driven by an actuator 17. Then, the amount of air taken into the combustion chamber 12 is adjusted by controlling the opening of the intake throttle valve 15. The air sucked into the intake passage 13 is mixed with the fuel injected from the fuel injection valve 16 provided in the combustion chamber 12 to become an air-fuel mixture, and burns in the combustion chamber 12. The intake passage 13 is provided with an air flow meter 31 for detecting the amount of air taken into the combustion chamber 12.

  The exhaust passage 14 is provided with a diesel particulate filter (hereinafter referred to as DPF) 22 as a filter that collects particulate matter (hereinafter referred to as PM) in the exhaust, and exhaust gas generated by combustion in the combustion chamber 12 is sent into the exhaust passage 14. It is. The DPF 22 is formed of a porous material, and thereby collects PM in the exhaust gas. The DPF 22 also collects ash, which is an incombustible component in the lubricating oil generated by the combustion of the lubricating oil in the internal combustion engine 10. That is, as described above, the lubricating oil is also used for lubricating the piston 24 and the cylinder 11, but a part of the lubricating oil used for lubricating the piston 24 and the cylinder 11 may leak into the combustion chamber 12. is there. When the lubricating oil leaks into the combustion chamber 12 in this way, the lubricating oil burns with the fuel in the combustion stroke of the internal combustion engine 10 and is discharged to the outside of the vehicle together with the exhaust. However, addition of sulfate ash and the like contained in the lubricating oil Since the agent remains unburned as ash, the unburned ash is collected in the DPF 22 in this way. During operation of the internal combustion engine 10, the lubricant remaining in the internal combustion engine 10 gradually decreases due to the combustion of the lubricant leaked into the combustion chamber 12.

  The DPF 22 carries an oxidation catalyst that oxidizes and purifies hydrocarbons (HC) and carbon monoxide (CO) in the exhaust, and is collected in the DPF 22 by a reaction triggered by the oxidation catalyst. The PM that has been burned (oxidized) is removed. The regeneration of the DPF 22 is performed by controlling the oxidation catalyst and the fuel injection valve 16 and the like by an electronic control unit 40 described later. That is, the oxidation catalyst, the electronic control unit 40, and the fuel injection valve 16 constitute a regeneration unit that regenerates the DPF 22 by burning the PM collected by the DPF 22.

  Various types of sensors are provided in the exhaust passage 14. Specifically, in the exhaust passage 14, an exhaust temperature sensor 32 that detects the temperature of the exhaust gas flowing into the DPF 22 is provided on the upstream side of the DPF 22, and a differential pressure ΔP (hereinafter simply referred to as “pressure difference” between the upstream side and the downstream side of the DPF 22). A differential pressure sensor 34 which is a differential pressure detecting means for detecting a differential pressure ΔP of the DPF 22 is provided.

  The vehicle is equipped with an electronic control unit 40 for performing various controls of the internal combustion engine 10. The electronic control unit 40 includes a CPU that executes various arithmetic processes related to engine control, a ROM that stores programs and data necessary for the control, a RAM that temporarily stores arithmetic results of the CPU, and signals between the outside The input / output port for inputting / outputting is provided.

  In addition to the exhaust temperature sensor 32 and the differential pressure sensor 34 described above, an NE sensor 35 that detects the engine speed, an accelerator sensor 36 that detects the accelerator operation amount, and an intake throttle valve 15 are provided at the input port of the electronic control unit 40. An intake throttle sensor 37 for detecting the opening is connected. The output ports of the electronic control unit 40 are connected to drive circuits such as the intake throttle valve 15 and the fuel injection valve 16. The electronic control unit 40 outputs a command signal to the drive circuit of each device connected to the output port in accordance with the engine operating state grasped by the detection signal input from each sensor. In this way, various controls such as the opening degree control of the intake throttle valve 15 and the fuel injection control from the fuel injection valve 16 are performed by the electronic control unit 40.

  Further, the electronic control unit 40 has a function as an ash amount deriving unit for deriving the amount of ash that is unburned lubricant accumulated in the DPF 22 based on the differential pressure ΔP detected by the differential pressure sensor 34. Yes. Specifically, the electronic control unit 40 is configured to derive the amount of ash deposited on the DPF 22 immediately after the DPF 22 is regenerated by the regenerating unit as the ash amount deriving unit. Here, the derivation of the amount of ash deposited on the DPF 22 includes not only deriving the actual amount of ash deposited but also deriving a physical quantity corresponding to the amount of accumulated ash. In the present embodiment, the electronic control unit 40 derives the differential pressure ΔP of the DPF 22 corresponding to the ash accumulation amount as the first differential pressure ΔP1 as ash amount deriving means.

Hereinafter, the principle of deriving the first differential pressure ΔP1 corresponding to the amount of accumulated ash will be described. FIG. 2 is a graph showing changes in the differential pressure ΔP of the DPF 22 while the vehicle is running.
The regeneration control of the DPF 22 by the regeneration means described above is performed when it is determined that the PM has accumulated in the DPF 22 to the extent that the regeneration of the DPF 22 is necessary. Every time Δd becomes longer, it is determined that a certain amount of PM has accumulated on the DPF 22, and this regeneration control is performed. This regeneration control is performed, for example, by setting the engine rotation speed to a speed higher than the speed corresponding to the idling operation during idling operation of the vehicle and supplying unburned fuel components to the oxidation catalyst. In addition, the catalyst is activated by the heat generated by oxidation on the catalyst and PM around the catalyst is combusted. The supply of the unburned fuel component to the catalyst in the regeneration control of the DPF 22 is performed after the fuel injection from the fuel injection valve 16 that contributes to the driving of the internal combustion engine 10, for example, post injection that is fuel injection in the exhaust stroke, etc. Is done by.

  In the internal combustion engine 10, by repeating such control, the amount of PM discharged outside the vehicle is reduced. Then, the differential pressure ΔP of the DPF 22 changes in the manner shown by the solid line in FIG. That is, when the driving of the vehicle is started, the differential pressure ΔP of the DPF 22 gradually increases due to accumulation of PM and ash, but when the travel distance becomes longer by the distance Δd and reaches the distance d, the DPF 22 is regenerated and PM Is removed, the differential pressure ΔP decreases. Since only the ash is substantially accumulated in the DPF 22 immediately after the regeneration, the electronic control unit 40 sets the differential pressure ΔP of the DPF 22 in this state to the first difference corresponding to the ash accumulation amount. Derived as a pressure ΔP1. Further, in the present embodiment, when the electronic control unit 40 as the ash amount deriving unit increases the first differential pressure ΔP1 by a predetermined pressure Δps or more, the amount of ash deposited on the DPF 22 is set to a predetermined value. It is determined that the deposition amount has increased by ΔM1 or more.

  Note that as the travel distance increases, the amount of lubricating oil consumed increases, so the amount of ash accumulated in the DPF 22 also increases, and the first differential pressure ΔP1 gradually increases. Therefore, the electronic control unit 40 may derive only the differential pressure ΔP immediately after the regeneration (the differential pressure ΔP at the points a1, a2,... In FIG. 2) as the first differential pressure ΔP1 corresponding to the amount of accumulated ash. The change estimated from the first differential pressure ΔP1 immediately after the regeneration of the DPF 22 (the chain line connecting the points a1, a2,... In FIG. 2) may be derived as the change in the first differential pressure ΔP1. In the present embodiment, for the sake of convenience, the first differential pressure ΔP1 is derived as changing linearly as shown by the one-dot chain line in FIG. 2, but the change mode of the first differential pressure ΔP1 Is not particularly limited.

  Furthermore, the electronic control unit 40 also has a function as a lubricating oil amount estimating unit that estimates the amount of lubricating oil remaining in the internal combustion engine 10 based on the ash amount derived by the ash amount deriving unit. . That is, since the incombustible component in the lubricating oil that becomes ash is contained in the lubricating oil at a predetermined concentration, the amount of ash deposited on the DPF 22 reflects the amount of lubricating oil consumed by combustion. Yes. And since it becomes possible to estimate the quantity of lubricating oil consumed by combustion based on the quantity of ash in this way, the quantity of lubricating oil remaining in the internal combustion engine 10 can also be estimated. Specifically, in the present embodiment, the electronic control unit 40 determines that the higher the first differential pressure ΔP1 corresponding to the ash accumulation amount is, the more lubricating oil is consumed by combustion. It is estimated that the amount of lubricating oil remaining in the internal combustion engine 10 decreases as the differential pressure ΔP1 increases. In addition, the electronic control unit 40 as the lubricating oil amount estimation means includes the first differential pressure ΔP1 corresponding to the ash accumulation amount when the lubricating oil is replaced last time (including when the lubricating oil is first supplied to the vehicle). ) Is increased by a predetermined pressure Δps or more, the ash accumulation amount is increased by the predetermined accumulation amount ΔM1 or more, so that it is determined that the consumption amount of the lubricating oil has become the predetermined consumption amount D or more. In the electronic control unit 40 as the estimating means, the amount of the lubricating oil remaining in the internal combustion engine 10 is equal to or less than the predetermined remaining amount W because the consumption amount of the lubricating oil is equal to or greater than the predetermined consumption amount D. When it is estimated in this way, it is determined that the present time is the time for replacing the lubricating oil, and the user (driver) of the vehicle is notified of the time for replacing the lubricating oil. Note that a lamp that can be visually recognized by the user is provided in the vehicle interior of the vehicle (not shown), and notification of the replacement time of the lubricating oil is performed by the electronic control device 40 turning on this lamp. As described above, the lubricating oil amount estimating apparatus according to the present embodiment includes the electronic control unit 40, the differential pressure sensor 34, the lamp, the oxidation catalyst, and the fuel injection valve 16.

  Here, the lubricating oil in the oil pan 29 is supplied to each sliding portion by an oil pump (not shown), and the discharge pressure of the oil pump decreases when the liquid level of the lubricating oil in the oil pan 29 drops to a predetermined position. Decreases rapidly. Conventionally, the discharge pressure of the oil pump is detected by a pressure sensor, and the user is notified of the replacement timing of the lubricating oil at the timing when the discharge pressure suddenly decreases. However, when the discharge pressure of the oil pump drops suddenly in this way, it is in a state that the replacement timing of the lubricating oil must be performed, and the replacement of the lubricating oil is performed immediately after notification of such replacement timing of the lubricating oil. If this is not done, there is a risk that lubrication will not be performed properly at each sliding portion of the internal combustion engine 10.

  Therefore, in the present embodiment, the predetermined remaining amount W of the lubricating oil that serves as a reference for notifying the replacement timing of the lubricating oil is set to an amount slightly larger than the amount of the lubricating oil when the discharge pressure of the oil pump rapidly decreases. Is set. Therefore, in this embodiment, even if the notification of the replacement timing of the lubricating oil is made, there is some time allowance until the time when the replacement of the lubricating oil must actually be performed. Even when the operation is not performed, if the lubricating oil is replaced within a certain period after the notification is made, the sliding portions of the internal combustion engine 10 are appropriately lubricated. That is, the notification of the replacement time of the lubricating oil in the present embodiment does not notify that it is a time when the replacement of the lubricating oil must be performed immediately, but is a time when the replacement of the lubricating oil is substantially required. Is to inform you that is approaching.

Hereinafter, estimation of the amount of lubricating oil performed by the electronic control unit 40 will be described with reference to FIGS. 3 and 4. FIG. 3 is a flowchart showing a lubricating oil amount estimation routine.
As shown in FIG. 3, when the lubricating oil amount estimation routine is started, it is determined in step S11 whether or not a condition for detecting the differential pressure ΔP of the DPF 22 for estimating the lubricating oil amount is satisfied. The Specifically, as the determination of the detection condition of the differential pressure ΔP, it is determined whether the internal combustion engine 10 is currently in a stable operating state and immediately after the regeneration control of the DPF 22 is finished. In step 11, by determining whether or not the DPF 22 has just been regenerated in this way, the differential pressure ΔP detected by the differential pressure sensor 34 becomes the first differential pressure ΔP1 corresponding to the amount of accumulated ash. It can be determined whether or not. In the determination as to whether the internal combustion engine 10 is in a stable operating state, for example, the internal combustion engine 10 is in an operating state, or the water temperature of the internal combustion engine 10 is equal to or higher than a predetermined temperature and is not immediately after the start of the operation of the internal combustion engine 10. In addition, it is determined whether or not the three conditions that the vehicle is traveling at a constant speed and the exhaust flow rate in the exhaust passage 14 is in a substantially steady state are satisfied. The third condition is that the exhaust flow rate in the exhaust passage 14 fluctuates when the vehicle is accelerating or decelerating, and the differential pressure ΔP detected by the differential pressure sensor 34 is not stable and may not be an accurate value. Therefore, it is determined whether or not the condition that the vehicle is traveling at a constant speed and not during acceleration operation or deceleration operation is satisfied. The constant speed here may be a specific speed or an arbitrary speed. That is, although the differential pressure ΔP of the DPF 22 changes as the vehicle speed changes, a correlation between the differential pressure ΔP (first differential pressure ΔP1) at each speed and the amount of ash accumulated on the DPF 22 should be derived in advance. Thus, immediately after the regeneration of the DPF 22, the amount of lubricating oil can be estimated based on the differential pressure ΔP of the DPF 22 at an arbitrary speed. That is, FIG. 4 shows a correlation between the first differential pressure ΔP1 and the amount of ash deposited on the DPF 22, but the map shown in FIG. 4 may be derived in advance at an arbitrary speed.

  In step S11, if it is determined that the internal combustion engine 10 is in a stable operating state and the DPF 22 is immediately after regeneration, the process proceeds to step S12, and if any of these conditions is not satisfied, the process proceeds to the end. . Note that the detection condition of the differential pressure ΔP in step S11 can be changed as appropriate, a part of the condition may be omitted, or another condition may be added.

  In step S12, it is determined whether or not the differential pressure ΔP detected by the differential pressure sensor 34 has increased by a predetermined pressure Δps or more than when the lubricating oil was changed last time. That is, since the differential pressure ΔP detected in step S12 is the differential pressure ΔP detected after satisfying the determination condition of step S11, the differential pressure ΔP detected here corresponds to the amount of ash accumulated. 1 differential pressure ΔP1. Therefore, if the differential pressure ΔP is increased by the predetermined pressure Δps or more than the previous replacement of the lubricating oil, the amount of ash accumulated in the DPF 22 is increased by the predetermined accumulation amount ΔM1 or more. It is determined that the amount has decreased to the predetermined remaining amount W or less. And if it is affirmation determination in this step S12, it will move to step S13 and the electronic control apparatus 40 will light the lamp | ramp in a vehicle interior to alert | report to a user that it is the replacement | exchange time of lubricating oil. If it is determined in step S12 that the differential pressure ΔP has not increased by the predetermined pressure Δps or more, it is determined that the amount of lubricating oil has not decreased to the predetermined remaining amount W. It moves to the end without being notified of the time.

  Here, step S12 will be described with reference to FIG. FIG. 4 shows the correlation between the first differential pressure ΔP1, which is the differential pressure ΔP detected in step S12, and the amount of ash deposited on the DPF 22, as described above. When the lubricating oil is first supplied, FIG. Both the first differential pressure ΔP1 and the ash accumulation amount are shown as “0” for convenience. For example, if the differential pressure ΔP detected in step S12 is the pressure po, the first differential pressure ΔP1 has not yet increased by a predetermined pressure Δps or more than when the lubricating oil was first supplied, and thus accumulated in the DPF 22. The amount of ash does not increase by a predetermined amount ΔM1 or more at first. Therefore, in this case, it is determined that the amount of the lubricating oil has not decreased to the predetermined remaining amount W that serves as a reference for notifying the replacement of the lubricating oil, and no notification of the replacement time of the lubricating oil is made. Then, when the differential pressure ΔP detected in step S12 becomes the pressure ps, the first differential pressure ΔP1 is increased by a predetermined pressure Δps compared to when the lubricating oil was first supplied, so that the ash accumulation amount is also predetermined. The accumulated amount ΔM1 is increased to become the accumulated amount M1, and it is determined that the amount of lubricating oil in the internal combustion engine 10 has decreased to a predetermined remaining amount W or less, and the lubricating oil replacement timing is notified. In this way, the user can recognize the replacement timing of the lubricating oil by lighting the lamp, and the notification of the replacement timing is made earlier than the timing at which the actual replacement of the lubricating oil is required. Therefore, even if a certain period of time has passed since this notification and the lubricating oil is replaced, the sliding portions of the internal combustion engine 10 are properly lubricated. That is, the user can change the lubricating oil with a certain amount of time after the notification of the replacement timing of the lubricating oil is performed.

  When the lubricating oil is replaced, the electronic control unit 40 as the lubricating oil amount estimation means uses the amount of ash accumulated in the DPF 22 when the replacement is performed as a reference amount, When the amount of oil increases by a predetermined amount ΔM1 or more than the reference amount, it is estimated that the amount of lubricating oil after replacement has decreased again to the predetermined amount, and the user is notified of the replacement timing of the lubricating oil again. That is, in FIG. 4, for example, even when the replacement time is notified when the first differential pressure ΔP1 becomes the pressure ps, the lubricating oil is not replaced at this pressure ps, and the amount of accumulated ash is M2. It is assumed that the lubricating oil is exchanged when the first differential pressure ΔP1 is the pressure pt. In that case, the estimation of the amount of lubricating oil by the electronic control unit 40 is reset by this replacement, and the lamp is turned off. Then, when the first differential pressure ΔP1 becomes equal to or higher than the pressure (pt + Δps) increased by the predetermined pressure Δps or more with respect to the pressure pt, the electronic control unit 40 also increases the ash accumulation amount by the predetermined accumulation amount ΔM1 (M2 + ΔM1). Thus, it is estimated that the amount of lubricating oil after replacement has decreased again to a predetermined remaining amount W or less, and the lubricating oil replacement timing is notified.

  2, as the first differential pressure ΔP1, not only the differential pressure ΔP at the points a1, a2,... In FIG. In this case, the first differential pressure ΔP1 is derived even if not immediately after the regeneration of the DPF 22. Therefore, in this case, in the flowchart of FIG. 3, in step S11, it is not necessary to determine whether or not the regeneration control of the DPF 22 is completed. In step S12, the first differential pressure ΔP1 indicated by the one-dot chain line in FIG. It is determined whether the pressure has increased by a predetermined pressure Δps or more.

As described above in detail, according to the lubricating oil amount estimating apparatus for an internal combustion engine of the present embodiment, the following effects can be obtained.
(1) The lubricating oil amount estimating apparatus according to the present embodiment corresponds to the amount of ash accumulated in the DPF 22 by the electronic control unit 40 based on the pressure difference ΔP between the upstream side and the downstream side of the DPF 22 of the internal combustion engine 10. By deriving one differential pressure ΔP1, the amount of lubricating oil remaining in the internal combustion engine is estimated. That is, since the incombustible component in the lubricating oil to be ash is contained in the lubricating oil at a predetermined concentration, the amount of ash deposited on the DPF 22 reflects the amount of lubricating oil consumed by combustion. Thus, by deriving the first differential pressure ΔP1 corresponding to the amount of ash accumulated in the DPF 22, the amount of lubricating oil consumed by combustion can be derived. In this way, the lubricating oil remaining in the internal combustion engine 10 is detected by detecting the differential pressure ΔP of the DPF 22 provided for the purpose of collecting PM in the internal combustion engine 10 without providing a lubricating oil level sensor or the like. The amount of oil can be estimated. Further, the amount of lubricating oil remaining in the internal combustion engine 10 can be estimated by a simple method of detecting the differential pressure ΔP without actually deriving the amount of ash accumulated in the DPF 22.

  (2) The lubricating oil amount estimation device of the present embodiment detects the differential pressure ΔP immediately after the DPF 22 is regenerated by the regenerating means, and sets this as the first differential pressure ΔP1 corresponding to the ash accumulation amount in the DPF 22. That is, the differential pressure ΔP immediately after the regeneration of the DPF 22 is the differential pressure ΔP in a state in which the PM accumulated in the DPF 22 is removed and only ash is substantially accumulated in the DPF 22, so that the PM collected in the DPF 22 It is derived as the first differential pressure ΔP1 corresponding to the amount of accumulated ash without being influenced by. In this way, the first differential pressure ΔP1 corresponding to the amount of ash can be derived without being affected by the PM accumulated in the DPF 22, and based on this, the amount of lubricating oil remaining in the internal combustion engine can be accurately determined. Can be estimated.

  (3) In the lubricating oil amount estimation device of the present embodiment, the first differential pressure ΔP1 of the DPF 22 increases by a predetermined pressure Δps or more from the time when the lubricating oil is first supplied or replaced, and the amount of accumulated ash is predetermined. When it is determined that the accumulated amount ΔM1 has increased, the amount of lubricating oil remaining in the internal combustion engine 10 is estimated to have decreased to a predetermined remaining amount W, and the replacement timing of the lubricating oil is notified. The predetermined remaining amount W is set to be larger than the lubricating oil amount that is a reference for notification of the conventional replacement time when the replacement of the lubricating oil is notified by a decrease in the discharge pressure of the oil pump. In the present embodiment, since the predetermined remaining amount W of the lubricating oil amount is appropriately set as described above, it is possible to notify the replacement timing of the lubricating oil earlier than in the past, and the user can It is possible to replace the lubricating oil with a time margin. That is, even if it is not immediately after the notification of the replacement time of the lubricating oil, if the lubricating oil is replaced within a certain period after the notification is received, the sliding portions in the internal combustion engine 10 are appropriately lubricated. be able to.

  When the lubricating oil is exchanged, if the first differential pressure ΔP1 rises by a pressure Δps or more with reference to the first differential pressure ΔP1 corresponding to the ash accumulation amount at the time of the exchange, lubrication in the internal combustion engine 10 is performed. It is estimated that the oil amount has decreased to a predetermined remaining amount W or less again. Therefore, even if the replacement of the lubricating oil is performed a plurality of times, the amount of the lubricating oil remaining in the engine 10 can be appropriately estimated each time.

(Second Embodiment)
Next, a second embodiment that embodies the lubricating oil amount estimation device for an internal combustion engine of the present invention will be described with reference to FIG. 5 and FIG. 1 of the first embodiment. In the second embodiment, the differential pressure ΔP of the DPF 22 when it is estimated that the PM remaining in the DPF 22 has reached the minimum amount (including the case of “0”) immediately after the regeneration means regenerates the DPF 22. Is derived as a first differential pressure ΔP1 corresponding to the amount of ash deposited on the DPF 22.

  That is, in the first embodiment, PM is completely removed immediately after the regeneration of the DPF 22, and the differential pressure ΔP of the DPF 22 immediately after the regeneration is derived as the first differential pressure ΔP1 corresponding to the ash accumulation amount. I am doing so. However, depending on the driving state of the vehicle, even if the regeneration control of the DPF 22 is performed, the regeneration control may be interrupted before the regeneration of the DPF 22 is completely completed. PM is still deposited on the DPF 22. That is, the differential pressure ΔP of the DPF 22 detected in this state is a pressure corresponding to the ash accumulation amount and the remaining PM accumulation amount, and cannot be said to correspond only to the ash accumulation amount. Therefore, in the present embodiment, the differential pressure ΔP of the DPF 22 detected when the PM remaining in the DPF 22 is estimated to be the minimum amount immediately after the regeneration of the DPF 22 is calculated. Is derived as a first differential pressure ΔP1 corresponding to.

  Specifically, also in the present embodiment, as shown in FIG. 5, the regeneration control of the DPF 22 by the regeneration unit is, for example, that a certain amount of PM accumulates on the DPF 22 every time the travel distance of the vehicle increases by the distance Δd. The amount of PM that is determined and discharged to the outside of the vehicle is reduced. The differential pressure ΔP of the DPF 22 changes in the manner shown in FIG. That is, when the driving of the vehicle is started, the differential pressure ΔP of the DPF 22 gradually increases due to accumulation of PM and ash, but when the travel distance reaches the distance d, the DPF 22 is regenerated and PM is removed. In addition, the differential pressure ΔP decreases. Here, in this embodiment, the differential pressure ΔP immediately after the regeneration of the DPF 22 at the distance d becomes the pressure b1, and the differential pressure ΔP immediately after the regeneration of the DPF 22 at the next distance 2d becomes the pressure b2, which is lower than the pressure b1. As the travel distance becomes longer, the amount of ash deposited on the DPF 22 increases and the first differential pressure ΔP1 corresponding to the ash accumulation amount increases, but when the travel distance is 2d than when the distance is d. Since the differential pressure ΔP is detected to be small, it is considered that the influence of PM deposited on the DPF 22 is smaller at the distance 2d. That is, in the DPF 22, when the distance immediately after the regeneration at the distance d and the distance 2d is compared, it is determined that the amount of PM remaining in the DPF 22 is smaller immediately after the regeneration of the DPF 22 at the distance 2d. .

  Since the first differential pressure ΔP1 corresponding to the ash accumulation amount increases with the travel distance, it is determined whether or not the amount of PM remaining in the DPF 22 immediately after the regeneration of the DPF 22 has become the minimum amount. This is determined not by the magnitude of the detected differential pressure ΔP but by the rate of change of the differential pressure ΔP. That is, in this embodiment, immediately after the regeneration of the DPF 22, when it is estimated that the differential pressure ΔP with respect to the travel distance of the vehicle, that is, “differential pressure ΔP / travel distance” is minimized, the PM remaining in the DPF 22 Is determined to be the minimum amount. Specifically, when the rate of change of the differential pressure ΔP immediately after each regeneration of the DPF 22 shown in FIG. 5 is examined, the rate of change b4 / 4d of the differential pressure ΔP immediately after the regeneration of the distance 4d is the rate of change b2 immediately after the previous regeneration. / 2d and the rate of change b3 / 3d immediately after the previous reproduction are continuously reduced. Therefore, it is estimated that the PM remaining in the DPF 22 has become the minimum amount immediately after the regeneration of the DPF 22 at the distance 4d. The first differential pressure ΔP1 corresponding to the amount of accumulated ash is estimated to change based on the rate of change b4 / 4d of the differential pressure ΔP at the distance 4d, and only corresponds to the ash that is not affected by PM. It is estimated that the first differential pressure ΔP1 changes in the manner shown by the one-dot chain line in FIG. In the present embodiment, when the first differential pressure ΔP1 indicated by the alternate long and short dash line rises by a predetermined pressure Δps or more than the first differential pressure ΔP1 at the time of replacement of the lubricating oil, the lubricating oil remaining in the internal combustion engine 10 Is estimated to have decreased to a predetermined remaining amount W, and the replacement timing of the lubricating oil is notified. Other configurations and operations not specifically described are the same as those in the first embodiment.

According to this embodiment described in detail above, the same effects as the effects (1) and (3) described in the first embodiment and the following effect (4) can be achieved.
(4) In the lubricating oil amount estimation device of the present embodiment, the differential pressure ΔP of the DPF 22 when the amount of PM remaining in the DPF 22 is estimated to be the minimum immediately after the regeneration of the DPF 22 is calculated as the DPF 22 Is derived as a first differential pressure ΔP1 corresponding to the amount of ash deposited on the surface. The transition of the first differential pressure ΔP1 is estimated based on the first differential pressure ΔP1 when the amount of PM becomes the minimum amount, and the amount of lubricating oil in the internal combustion engine 10 is estimated. Therefore, even if the regeneration control of the DPF 22 is interrupted halfway and the regeneration of the DPF 22 is not performed completely every time, the amount of ash accumulated on the DPF 22 can be accurately derived. The amount of lubricating oil can be estimated more accurately based on the amount of ash thus accurately derived.

(Third embodiment)
Next, a third embodiment that embodies the lubricating oil amount estimation device for an internal combustion engine of the present invention will be described with reference to FIG. 1 used in the first embodiment. In the third embodiment, the electronic control unit 40 derives the deposition amount of all the deposits deposited on the DPF 22 and the deposition amount of PM, and is based on the deposition amount of these all deposits and the deposition amount of PM. Thus, the amount of ash deposited on the DPF 22 is derived. The electronic control unit 40 estimates the amount of lubricating oil remaining in the internal combustion engine 10 based on the amount of ash derived in this way. That is, this embodiment differs from the first and second embodiments described above in that the first corresponding to the ash accumulation amount is detected by detecting the differential pressure ΔP of the DPF 22 immediately after the regeneration of the DPF 22 by the regeneration means. The amount of lubricating oil is not estimated in such a manner that the differential pressure ΔP1 is derived.

  Specifically, the differential pressure ΔP of the DPF 22 increases as the amount of total deposits deposited on the DPF 22 increases, but the electronic control unit 40 has a correlation between the differential pressure ΔP and the total amount of deposits deposited on the DPF 22. The relationship is input and set in advance, and the control device 40 derives the total amount of deposits in the DPF 22 based on the differential pressure ΔP detected by the differential pressure sensor 34 and this correlation. In deriving the PM accumulation amount in the DPF 22, the electronic control unit 40 first calculates the PM emission amount based on the engine speed, the fuel injection amount, etc., and also based on the temperature of the DPF 22, the intake air amount, etc. The PM combustion amount in the DPF 22 is calculated. Based on the PM emission amount and the PM combustion amount, the PM accumulation amount in the DPF 22 is derived. Specifically, the amount of accumulated PM is derived at any time during operation, and the amount of PM burned by regeneration control of the DPF 22 is added by adding the newly discharged PM emission amount to the previously derived PM accumulation amount. By subtracting, the amount of accumulated PM is derived. In the present embodiment, the electronic control unit 40 derives the ash deposition amount by subtracting the PM deposition amount from the deposition amount of the total deposit in the DPF 22 derived in this way, and the ash deposition amount is calculated. Based on the amount, the amount of lubricating oil remaining in the internal combustion engine 10 is estimated.

  As described above in detail, according to the lubricating oil amount estimation device of the present embodiment, the first embodiment has the effects according to (1) and (3) and the following effect (5). be able to. That is, in (1) and (3) of the first embodiment, the effect by deriving the first differential pressure ΔP1 corresponding to the ash accumulation amount is described as the ash accumulation amount. Even when the amount of accumulated oil is actually derived, the amount of lubricating oil can be estimated in the same manner, and the replacement time of the lubricating oil can be notified early. Other configurations, operations, and effects are the same as those in the first and second embodiments.

  (5) In the lubricating oil amount estimation apparatus of this embodiment, the electronic control unit 40 derives the accumulation amount of all deposits and the PM accumulation amount deposited on the DPF 22, and the accumulation amount of these all deposits The amount of ash deposited on the DPF 22 is derived based on the amount of PM deposited. Then, it is easier to derive the amount of all deposits accumulated in the DPF 22 than to derive the amount of ash accumulated in the DPF 22 based on the differential pressure ΔP detected by the differential pressure sensor 34. The amount of accumulated PM can be derived as appropriate depending on the operating state of the internal combustion engine 10 and the like. Further, the deposition amount of all the deposits and the deposition amount of PM can be derived regardless of the timing of regeneration control of the DPF 22. Therefore, since the amount of ash can be derived not only immediately after regeneration of the DPF 22, the amount of lubricating oil remaining in the internal combustion engine 10 can be estimated at any time.

(Other embodiments)
In addition, you may change the said embodiment as follows.
In the first and second embodiments, when the regeneration control of the DPF 22 is completely performed or when it is not completely performed, the amount of PM deposited on the DPF 22 becomes the minimum amount. The differential pressure ΔP is derived as a first differential pressure ΔP1 corresponding to the amount of ash accumulated on the DPF 22. However, when the regeneration control of the DPF 22 is completed, even if PM remains in the DPF 22, the differential pressure ΔP of the DPF 22 detected at this time corresponds to the amount of ash accumulated in the DPF 22. Alternatively, it may be simply derived as one differential pressure ΔP1.

  In each of the above embodiments, the differential pressure ΔP of the DPF 22 detected by the differential pressure sensor 34 is used only for deriving the amount of ash accumulated on the DPF 22. However, in the control of the internal combustion engine 10, for example, when the differential pressure ΔP detected by the differential pressure sensor 34 is too high, it is determined that PM is excessively accumulated on the DPF 22 or the like. The differential pressure ΔP detected by 34 may be appropriately used for other controls in the internal combustion engine 10. In this case, in other words, since the differential pressure sensor 34 provided for another use of the internal combustion engine 10 can be used for the lubricating oil amount estimating device, it is separately provided for estimating the lubricating oil amount. There is no need to provide the differential pressure sensor 34. In order to detect the differential pressure ΔP, pressure sensors may be provided on the upstream side and the downstream side of the DPF 22 in place of the differential pressure sensor 34. In addition, a pressure sensor is provided only on the upstream side of the DPF 22, and the pressure on the downstream side is estimated by deriving the atmospheric pressure and the pressure loss of the exhaust gas flowing through the downstream pipe, and thereby the upstream and downstream sides of the DPF 22 are estimated. The differential pressure ΔP may be detected.

  In each of the above embodiments, in order to derive the amount of ash accumulated on the DPF 22, the differential pressure ΔP of the DPF 22 is detected. However, a method other than detecting the differential pressure ΔP of the DPF 22, for example, ash accumulation The amount of ash deposited on the DPF 22 may be derived by a method of calculating the deposition amount by directly detecting the thickness.

  In each of the above embodiments, the lubricating oil amount estimation device notifies that it is time to replace the lubricating oil when the lubricating oil amount of the internal combustion engine 10 is equal to or less than the predetermined remaining amount W. The predetermined remaining amount W is set to be larger than the amount of lubricating oil at which the discharge pressure of the oil pump rapidly decreases. However, the predetermined remaining amount W is not particularly limited, and may be the same amount as when the discharge pressure of the oil pump rapidly decreases, or may be set as appropriate by a user or the like. Also, when the predetermined remaining amount W is set to be larger than the lubricating oil amount at which the discharge pressure of the oil pump suddenly decreases, the lamp is turned on when the lubricating oil amount becomes the predetermined remaining amount W or less. The notification of the timing may be performed, and thereafter, when the discharge pressure of the oil pump rapidly decreases, the notification of the replacement timing of the lubricating oil may be performed again by another lamp.

  Further, since the amount of lubricating oil in the internal combustion engine 10 can be estimated at any time by deriving the amount of ash accumulated in the DPF 22, the amount of lubricating oil may be notified to the user as needed. In this case, for example, a meter or the like indicating how much lubricating oil remains in the passenger compartment may be provided.

Note that the notification of the lubricating oil amount and the replacement time of the lubricating oil may be performed by a buzzer or the like in addition to the lamp and meter described above.
In each of the above embodiments, the lubricating oil amount estimation device notifies that it is time to replace the lubricating oil when the lubricating oil amount of the internal combustion engine 10 is equal to or less than the predetermined remaining amount W. However, the lubricating oil amount estimation device may merely estimate that the lubricating oil amount of the internal combustion engine 10 is equal to or less than the predetermined remaining amount W, and may not perform notification.

1 is a schematic diagram of an in-vehicle internal combustion engine to which a lubricating oil amount estimation device is applied in a first embodiment according to the present invention. In 1st Embodiment, the graph which shows the change of the differential pressure | voltage (DELTA) P of the upstream and downstream of DPF during vehicle driving | running | working. The flowchart which shows the estimation routine of lubricating oil amount in 1st Embodiment. 5 is a graph showing the amount of ash deposited on the DPF with respect to the first differential pressure ΔP1 in the first embodiment. In 2nd Embodiment, the graph which shows the change of the differential pressure | voltage (DELTA) P of the upstream and downstream of DPF during vehicle travel.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Cylinder, 12 ... Combustion chamber, 13 ... Intake passage, 14 ... Exhaust passage, 15 ... Intake throttle valve, 16 ... Fuel injection valve, 17 ... Actuator, 18 ... Intake valve, 19 ... Exhaust valve, DESCRIPTION OF SYMBOLS 21 ... Crankcase, 22 ... Diesel particulate filter (DPF), 23 ... Crankshaft, 24 ... Piston, 29 ... Oil pan, 31 ... Air flow meter, 32 ... Exhaust temperature sensor, 34 ... Differential pressure sensor, 35 ... NE sensor , 36 ... accelerator sensor, 37 ... intake throttle sensor, 40 ... electronic control unit.

Claims (7)

A filter disposed in an exhaust passage of an internal combustion engine for collecting particulate matter discharged from the engine;
Ash amount deriving means for deriving the amount of ash deposited on the filter;
Lubricating oil for an internal combustion engine, comprising: a lubricating oil amount estimating means for estimating the amount of lubricating oil remaining in the engine based on the ash amount derived by the ash amount deriving means Quantity estimation device. In claim 1,
A differential pressure detecting means for detecting a differential pressure between the upstream side and the downstream side of the filter;
The ash amount deriving means derives the ash amount based on the differential pressure of the filter detected by the differential pressure detecting means. In claim 1 or 2,
Regenerating means for regenerating the filter by burning the particulate matter collected by the filter;
The ash amount deriving means derives the amount of ash accumulated in the filter immediately after the filter is regenerated by the regenerating means. In claim 3,
The ash amount deriving means derives the ash amount deposited on the filter when it is estimated that the particulate matter remaining in the filter has reached a minimum amount in the regeneration of the filter performed by the regeneration means. An apparatus for estimating the amount of lubricating oil for an internal combustion engine. In claim 1 or 2,
The ash amount deriving means derives the accumulation amount of the entire deposit and the accumulation amount of the particulate matter deposited on the filter, and the accumulation amount of the entire deposit and the accumulation amount of the particulate matter The amount of said ash is derived based on this, The lubricating oil amount estimation apparatus of the internal combustion engine characterized by the above-mentioned. In any one of Claims 1-5,
The lubricating oil amount estimating means estimates that the amount of the lubricating oil remaining in the engine has decreased to a predetermined amount when the amount of ash accumulated on the filter reaches a predetermined amount of accumulated oil. An apparatus for estimating the amount of lubricating oil for an internal combustion engine, characterized by notifying the replacement time. In any one of Claims 1-6,
The amount of ash estimated by the ash amount deriving unit is determined based on the amount of ash accumulated on the filter when the lubricating oil is replaced. When the amount of oil increases by a predetermined amount from the reference amount, it is estimated that the amount of the lubricating oil remaining in the internal combustion engine has decreased to a predetermined amount.

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