JP2006348792A - Lubricating oil consumption estimation device and exhaust purification device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricating oil consumption estimation device for an internal combustion engine capable of more accurately estimating consumption of lubricating oil and an exhaust emission control device capable of always accurately estimating ash accumulation quantity of DPF by using the lubricating oil consumption quantity estimation device. <P>SOLUTION: Instantaneous base oil consumption QOBS is calculated according to engine rotation speed NE and fuel injection quantity QINJ (S101), and collection coefficient K is calculated according to cooling water temperature TW (S102). Instantaneous oil consumption QOT is calculated by multiplying instantaneous base oil consumption QOBS by correction coefficient K (S103), and total oil consumption QOIL is calculated by integrating instantaneous oil consumption QOT(S104). Ash accumulation quantity GASH of the DPF 12 is calculated according to total oil consumption QOIL (S4). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lubricating oil consumption estimation device that estimates a consumption amount of lubricating oil in an internal combustion engine, and an exhaust purification device that includes this lubricating oil consumption estimation device.

  In an internal combustion engine, particularly a diesel engine, a diesel particulate filter (hereinafter referred to as “DPF”) that collects particulates (particulate matter) contained in exhaust gas has been widely used. Since there is a limit to the amount of particulates that can be collected by the DPF, regeneration processing for burning the particulates accumulated in the DPF is executed in a timely manner.

  On the other hand, the lubricating oil of the internal combustion engine gradually decreases with long-term use of the engine. This is because the lubricating oil is burned and discharged in small amounts. When the lubricating oil burns, the metallic detergent contained in the lubricating oil also burns and ash (ash) is generated. This ash is mainly composed of a metal component (Mg, Ca, etc.) of a metallic detergent and a sulfate compound (sulfate ash) produced by oxidation of sulfur in the fuel. In an engine equipped with a DPF, Deposit on DPF. When ash accumulates on the DPF, the DPF's ability to collect the particulates that should be collected decreases, and the particulates become over-deposited, which may cause abnormal temperature rise when the DPF is regenerated. There is. Therefore, in order to avoid such an abnormal situation, it is necessary to accurately estimate the ash accumulation amount of the DPF.

Patent Document 1 discloses a method for calculating an estimated amount of ash accumulation by calculating an ash generation amount Ash per unit time in accordance with an engine torque and a rotational speed, and integrating the ash generation amount Ash. It is shown.
Japanese Patent Application Laid-Open No. 2004-228561 detects a pressure difference ΔPdpf between the upstream pressure and the downstream pressure of the DPF, and estimates the ash deposition amount ASH based on the differential pressure ΔPdpf immediately after the DPF regeneration process is executed. It is shown.

JP 2002-242660 A JP 2004-21650 A

  The amount of ash deposited on the DPF is considered to be substantially proportional to the consumption (decrease amount) of the lubricating oil of the engine, but the lubricating oil consumption does not depend only on the torque and the rotational speed of the engine. Therefore, in the method disclosed in Patent Document 1, the estimation accuracy of the ash deposition amount is lowered, and the calculated value of the particulate deposition amount is excessively large or small. There is a concern that the fuel consumption and exhaust characteristics may deteriorate due to an increase in the number of executions of the regeneration process.

  Further, the technique disclosed in Patent Document 2 has a drawback that the estimation time of the ash deposition amount is limited to the time point when the regeneration process is completed (all accumulated particulates are burned).

  The present invention has been made in consideration of the above-mentioned points, and has as its first object to provide a lubricating oil consumption estimation device for an internal combustion engine that can estimate the consumption of the lubricating oil more accurately. It is a second object of the present invention to provide an exhaust emission control device capable of always accurately estimating the amount of accumulated DPF ash using the lubricating oil consumption estimation device.

  In order to achieve the above object, an invention according to claim 1 is a lubricating oil consumption estimation device that estimates a consumption amount of lubricating oil of the engine according to an operating parameter indicating an operating state of the internal combustion engine, The parameter includes a parameter indicating a temperature of the engine, and provides a lubricating oil consumption estimation device.

According to a second aspect of the present invention, in the lubricating oil consumption estimation device according to the first aspect, the parameter indicating the temperature of the engine is a cooling water temperature of the engine.
According to a third aspect of the present invention, in the lubricating oil consumption estimation device according to the second aspect, the basic consumption calculating means for calculating the basic consumption of the lubricating oil based on the engine speed and load. Correction means for correcting the basic consumption according to the cooling water temperature, and the lubricating oil consumption is estimated by integrating the corrected basic consumption.

  According to a fourth aspect of the present invention, there is provided an exhaust gas purification apparatus for an internal combustion engine comprising a particulate filter that collects particulates in the exhaust gas of the internal combustion engine. A deposit amount calculation that calculates the amount of lubricant ash generated by combustion of the lubricant deposited on the particulate filter based on the lubricant consumption estimated by the device and the lubricant consumption estimation device Means.

  According to the first aspect of the present invention, the lubricating oil consumption is estimated according to the operating parameter including the parameter indicating the temperature of the internal combustion engine. Lubricant consumption is correlated with the internal temperature state of the engine. For example, when the engine is cold, the gap between the cylinder and the piston tends to increase, and the amount of lubricating oil consumed tends to increase. On the other hand, after the warm-up is completed, the consumption amount of the lubricating oil is almost constant if the engine speed and the engine load are constant, and further, the evaporation amount of the lubricating oil tends to increase as the engine temperature rises. Therefore, accurate estimation is possible by estimating the lubricating oil consumption according to the engine operating parameters including the parameter indicating the engine temperature.

  According to the second aspect of the present invention, the engine cooling water temperature is used as a parameter indicating the engine temperature. Since the sensor for detecting the cooling water temperature is always provided, it is not necessary to provide a new sensor for estimating the lubricant consumption, and an increase in cost can be suppressed.

  According to the third aspect of the present invention, the basic consumption of the lubricating oil is calculated based on the engine speed and the engine load, the basic consumption is corrected according to the cooling water temperature, and the corrected basic consumption is calculated. By integrating, the lubricating oil consumption is estimated. Therefore, accurate estimation according to the intake air amount depending on the engine speed and the engine load and the coolant temperature can be performed.

  According to the fourth aspect of the present invention, the amount of lubricating oil ash generated by the combustion of the lubricating oil deposited on the particulate filter is based on the lubricating oil consumption estimated by the lubricating oil consumption estimation device. Calculated. Since the amount of accumulated oil ash on the particulate filter is considered to be approximately proportional to the amount of lubricant consumed, accurate lubrication can be achieved by using the estimated amount of lubricant consumed according to the operating parameters including the parameter indicating the engine temperature. The oil ash accumulation amount can be calculated. Therefore, it is possible to more accurately grasp the particulate accumulation amount of the particulate filter, and it is possible to prevent the regeneration process from being performed in an excessive deposition state or the regeneration process that is not actually required. As a result, abnormal temperature rise of the particulate filter or deterioration of fuel consumption and exhaust characteristics can be prevented.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing the configuration of an internal combustion engine equipped with an exhaust emission control device according to an embodiment of the present invention and its control device. An internal combustion engine (hereinafter simply referred to as “engine”) 1 is a diesel engine that directly injects fuel into a cylinder, and a fuel injection valve 15 is provided in each cylinder. The fuel injection valve 15 is electrically connected to an electronic control unit (hereinafter referred to as “ECU”) 20, and the valve opening time and timing of the fuel injection valve 15 are controlled by the ECU 20.

  The engine 1 includes an intake pipe 2 and an exhaust pipe 4. The exhaust pipe 4 is provided with a catalytic converter 11, a DPF 12, and a silencer 13 for purifying exhaust gas in this order from the upstream side. The catalytic converter 11 incorporates an oxidation catalyst for promoting the oxidation of hydrocarbons and carbon monoxide contained in the exhaust gas. Note that the catalytic converter 11 may be added with a NOx adsorbent that adsorbs NOx and a NOx reduction action.

  When the exhaust gas passes through the fine holes in the filter wall, the DPF 12 deposits soot, which is a particulate material mainly composed of carbon (C) in the exhaust gas, on the surface of the filter wall and the holes in the filter wall. Collect by letting. As a constituent material of the filter wall, for example, ceramics such as silicon carbide (SiC) or a porous metal body is used.

  If soot is collected up to the limit of the soot collecting ability of the DPF 12, that is, the accumulation limit, the exhaust pressure rises, so it is necessary to perform a regeneration process for burning the soot in a timely manner. In this regeneration process, post injection is performed in order to raise the temperature of the exhaust gas to the combustion temperature of the soot. The post-injection is fuel injection performed in the exhaust stroke by the fuel injection valve 15. The fuel injected by the post injection is mainly burned by the catalytic converter 11 and raises the temperature of the exhaust gas flowing into the DPF 12.

  Further, the intake pipe 2 is provided with an intake air flow rate sensor 21 for detecting the intake air flow rate GA of the engine 1, and the engine 1 is provided with a cooling water temperature sensor 22 for detecting the cooling water temperature TW. An exhaust temperature sensor 23 for detecting the exhaust temperature TE is provided on the upstream side of the catalytic converter 11 in the exhaust pipe 4, and a differential pressure sensor 24 for detecting a differential pressure DP between the upstream pressure and the downstream pressure of the DPF 12. Is provided. Detection signals from these sensors are supplied to the ECU 20. A crank angle position sensor 25 for detecting the rotation angle of the crankshaft of the engine 1 is provided, and the detection signal is supplied to the ECU 20. The rotational speed (rotational speed) NE of the engine 1 is calculated from the output of the crank angle position sensor.

  Further, other sensors (not shown), for example, an accelerator sensor that detects an accelerator pedal depression amount AP of a vehicle driven by the engine 1, an atmospheric pressure sensor that detects an atmospheric pressure PA, a vehicle speed sensor that detects a vehicle speed VP of the vehicle, and the like. The detection signals of these sensors are supplied to the ECU 20.

  The ECU 20 shapes input signal waveforms from various sensors, corrects the voltage level to a predetermined level, converts an analog signal value into a digital signal value, a central processing unit (hereinafter referred to as “CPU”). A storage circuit that stores various calculation programs executed by the CPU, calculation results, and the like, and an output circuit that supplies a control signal to the fuel injection valve 15 and the like.

  The ECU 20 calculates the fuel injection amount QINJ by the fuel injection valve 15 according to the accelerator pedal depression amount AP, and controls the valve opening time of the fuel injection valve 15 according to the calculated fuel injection amount QINJ. Further, the ECU 20 estimates the lubricating oil consumption of the engine 1 (hereinafter referred to as “oil consumption”), calculates the ash accumulation amount GASH of the DPF 12 according to the estimated oil consumption amount, and uses the ash accumulation amount GASH. Then, the particulate deposition amount GPM of the DPF 12 is calculated, and when the particulate deposition amount GPM exceeds the threshold value GPMTH, a regeneration process for burning the particulates deposited on the DPF 12 is executed.

  FIG. 2A is a flowchart showing a procedure for calculating the ash accumulation amount GASH and the particulate accumulation amount GPM of the DPF 12 and executing the regeneration control of the DPF 12, and FIG. 2B shows the total oil consumption amount QOIL. It is a flowchart which shows the process to calculate. The oil consumption calculation process is executed by the CPU of the ECU 20 every predetermined time.

  First, the oil consumption calculation process in FIG. 2B will be described. In step S101, the QOBS map shown in FIG. 3 is searched according to the engine operating state, specifically, the fuel injection amount QINJ indicating the engine load and the engine speed NE, and the instantaneous basic oil consumption QOBS is calculated. The QOBS map is set so that the instantaneous basic oil consumption QOBS increases as the engine speed NE increases and as the fuel injection amount QINJ increases. Curves L1 to L4 in FIG. 3 correspond to the cases where the fuel injection amount QINJ is the first value QINJ1, the second value QINJ2, the third value QINJ3, and the fourth value QINJ4, respectively. A value of 4 QINJ1 to QINJ4 satisfies the relationship of QINJ1 <QINJ2 <QINJ3 <QINJ4.

  In step S102, the K table shown in FIG. 4 is searched according to the cooling water temperature TW, and the correction coefficient K is calculated. The K table is set such that the correction coefficient K decreases as the cooling water temperature TW increases in the range where the cooling water temperature TW is equal to or lower than the first predetermined water temperature TW1 (for example, 50 to 60 ° C.), and the cooling water temperature TW is the first predetermined water temperature TW. In the range from the water temperature TW1 to the second predetermined water temperature TW2 (eg, 130 ° C.), the correction coefficient K is set to a substantially constant value regardless of the cooling water temperature TW, and in the range where the cooling water temperature TW is higher than the second predetermined water temperature TW2, The correction coefficient K is set to increase as the water temperature TW increases. That is, the K table is set in consideration of the following points. When the engine 1 is cold, the gap between the cylinder and the piston tends to increase and the instantaneous oil consumption tends to increase. After the warm-up is completed, the instantaneous oil consumption is constant if the engine speed NE and the engine load are constant. As the engine temperature rises further, the amount of lubricant evaporation tends to increase.

In step S103, the instantaneous basic oil consumption amount QOBS and the correction coefficient K are applied to the following equation (1) to calculate the instantaneous oil consumption amount QOT.
QOT = QOBS × K (1)
In step S104, the instantaneous oil consumption amount QOT is integrated by the following equation (2) to calculate the total oil consumption amount QOIL. QOIL on the right side of Equation (2) is the previously calculated value.
QOIL = QOIL + QOT (2)

  As described above, according to the processing of FIG. 2B, the instantaneous basic oil consumption QOBS calculated according to the engine speed NE and the fuel injection amount QINJ corresponds to the coolant temperature TW, which is a parameter indicating the engine temperature. Thus, the instantaneous oil consumption QOT is calculated by the correction coefficient K set in the above. Further, the total oil consumption QOIL is calculated by integrating the instantaneous oil consumption QOT. Therefore, it is possible to obtain an accurate oil consumption estimated value that takes into account the influence of the engine temperature.

Next, the flowchart of FIG. In step S1, the differential pressure DP is detected by the differential pressure sensor 24. In step S2, the exhaust volume flow rate QVE is calculated by the following equation (3).
QVE = GE × R × TEA / PE (3)

  Here, GE is the exhaust mass flow rate, and the fuel injection amount QINJ is converted into the fuel injection amount QINJS per unit time according to the engine speed NE, and the intake air flow rate GA and the fuel injection amount QINJS are added. Calculated. R is a gas constant, TEA is the detected exhaust temperature TE converted into an absolute temperature, and PE is the exhaust pressure upstream of the DPF 12. In the present embodiment, the exhaust pressure PE is calculated by adding the pressure loss DPS of the silencer 13 and the differential pressure DP detected by the differential pressure sensor 24 to the atmospheric pressure PA.

  In step S3, a GDPF map (not shown) is searched according to the exhaust volume flow rate QVE and the differential pressure DP, and the total deposition amount GDPF of the DPF 12 is calculated. The total deposition amount GDPF is the total amount of substances (oil ash and particulates) collected in the DPF 12, that is, the total of the ash deposition amount GASH and the particulate deposition amount GPM. The GDPF map is set so that the total deposition amount GDPF increases as the exhaust volume flow rate QVE decreases and the differential pressure DP increases.

  In step S4, the GASH table shown in FIG. 5 is searched according to the total oil consumption QOIL calculated by the process of FIG. 2B, and the ash deposition amount GASH is calculated. The GASH table is set so that the ash accumulation amount GASH is substantially proportional to the total oil consumption amount QOIL.

  In step S5, the particulate deposition amount GPM is calculated by subtracting the ash deposition amount GASH from the total deposition amount GDPF, and then it is determined whether or not the particulate deposition amount GPM is larger than the threshold value GPMTH (step S6). When this answer is negative (NO), the processing is immediately terminated, and when the particulate accumulation amount GPM exceeds the threshold value GPMTH, regeneration control of the DPF 12 is executed (step S7).

  As described above, according to the procedure shown in FIG. 2A, the ash deposition amount GASH is calculated according to the total oil consumption amount QOIL, and the particulate deposition is subtracted from the ash deposition amount GASH from the total deposition amount GDPF. The quantity GPM is calculated. Accordingly, the particulate accumulation amount GPM can be calculated more accurately, and the regeneration process can be executed at an optimal time. That is, it is possible to prevent the regeneration process of the DPF 12 from being performed in an excessive deposition state, or the unnecessary regeneration process from being performed even though the actual particulate deposition amount is small. As a result, abnormal temperature rise of the particulate filter or deterioration of fuel consumption and exhaust characteristics can be prevented.

  In this embodiment, ECU20 comprises a lubricating oil consumption estimation apparatus. Specifically, the process shown in FIG. 2B corresponds to a lubricating oil consumption estimation device, step S101 corresponds to basic consumption calculation means, and steps S102 and S103 correspond to correction means. Further, step S4 in FIG. 2A corresponds to the accumulation amount calculating means.

  The present invention is not limited to the embodiment described above, and various modifications can be made. For example, when oil ash accumulates on the DPF 12, the effective capacity of the DPF 12 for depositing particulates decreases. Therefore, the threshold GPMTH applied in step S6 of FIG. 2 (A) is set so that the ash accumulation amount GASH increases. You may make it change to a smaller value.

  Further, immediately after the completion of the complete regeneration process for completely burning the particulates accumulated in the DPF 12, the differential pressure DP is detected, and the ash accumulation amount GASHa is calculated according to the differential pressure DP and the exhaust volume flow rate QVE, and the total oil consumption Compared to the ash deposition amount GASH calculated according to the amount QOIL, the larger one (safe side) may be adopted as the true value.

The parameter indicating the engine temperature is not limited to the cooling water temperature TW. For example, a temperature sensor that detects the lubricating oil temperature TOIL may be provided, and the detected lubricating oil temperature TOIL may be used. Further, immediately after the cold start of the engine, the elapsed time TAS after the start may be used as a parameter indicating the engine temperature.
When the total oil consumption QOIL calculated by the process of FIG. 2B reaches a predetermined threshold value QOILTH, a warning lamp may be turned on.

The lubricating oil consumption estimation device of the present invention can be applied not only to a diesel internal combustion engine but also to a gasoline internal combustion engine.
The present invention can also be applied to an estimation of lubricating oil consumption and an exhaust purification device for a marine vessel propulsion engine such as an outboard motor having a vertical crankshaft.

It is a figure which shows the structure of the internal combustion engine and its control apparatus concerning one Embodiment of this invention. It is a flowchart which shows the procedure of the process performed with the electronic control unit shown in FIG. It is a figure which shows the QOBS map referred by the process shown in FIG. It is a figure which shows K table referred by the process shown in FIG. It is a figure which shows the GASH table referred by the process shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 4 Exhaust pipe 12 Diesel particulate filter 15 Fuel injection valve 20 Electronic control unit (lubricating oil consumption estimation apparatus, basic consumption calculation means, correction means, accumulation amount calculation means)
21 Intake air flow sensor 22 Cooling water temperature sensor 23 Exhaust temperature sensor 24 Differential pressure sensor 25 Crank angle position sensor

Claims (4)

  A lubricating oil consumption estimation device that estimates a consumption amount of lubricating oil of the engine according to an operating parameter indicating an operating state of the internal combustion engine, wherein the operating parameter includes a parameter indicating a temperature of the engine. Lubricating oil consumption estimation device.   The lubricating oil consumption estimation device according to claim 1, wherein the parameter indicating the temperature of the engine is a cooling water temperature of the engine.   Based on the engine speed and load, the basic consumption calculating means for calculating the basic consumption of the lubricating oil and the correcting means for correcting the basic consumption according to the cooling water temperature are corrected. The lubricating oil consumption estimation device according to claim 2, wherein the lubricating oil consumption is estimated by integrating the basic consumption. In an exhaust gas purification apparatus for an internal combustion engine comprising a particulate filter that collects particulates in the exhaust gas of the internal combustion engine,
The lubricating oil consumption estimation device according to any one of claims 1 to 3,
A deposit amount calculating means for calculating an amount of lubricant ash generated by combustion of the lubricant deposited on the particulate filter based on the lubricant consumption estimated by the lubricant consumption estimation device; An exhaust emission control device for an internal combustion engine, comprising:

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