JP2012149593A - Device for determining failure of oil level in internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for determining a failure of an oil level in an internal combustion engine, which can accurately determine the failure of the oil level irrespective of variation in the oil level.SOLUTION: The device includes: performing timing measurement of both normal time and failure time of the oil level based on a detection value of the oil level to temporarily determine whether it is normal or failure at the end of each trip based on a comparison of the normal time with the failure time for the trip; and performing final determination of presence of a failure based on a comparison of the number of times temporarily determined to be normal with the number of times temporarily determined to be failure.

Description

  The present invention relates to an oil level abnormality determination device for an internal combustion engine that detects an oil surface height of lubricating oil in an oil pan during engine operation and determines whether or not the lubricating oil supply state is abnormal.

  2. Description of the Related Art Conventionally, a device described in Patent Document 1 is known as a device for determining an abnormality in the oil level (oil level) of lubricating oil stored in an oil pan of an internal combustion engine. In the determination apparatus described in the document, when the state in which the oil level in the oil pan has decreased to the lower limit level reaches the reference time while the engine is stopped, it is determined that the oil level is abnormally decreased. During engine operation, it is determined that the oil level is abnormally low when the number of times that the oil level in the oil pan has been detected to the lower limit level reaches the reference number. This makes it possible to accurately determine whether or not the oil level has been lowered even when the engine is stopped, where the oil level does not fluctuate, or during the operation of the engine where the oil level moves up and down.

JP 2007-33435 A

  By the way, in a diesel engine equipped with a diesel particulate filter (DPF) that collects particulate matter (PM) in exhaust gas, regeneration control of DPF by post injection may be performed. In such a diesel engine, the fuel supplied by the post injection may be mixed with the oil without being burned and the lubricating oil may be diluted. And if such oil dilution with fuel progresses, the lubrication performance of the oil will deteriorate, so it is necessary to detect its occurrence. The occurrence of oil dilution can be confirmed by an increase in oil level.

  Here, if the abnormal increase in oil level due to oil dilution is performed in an aspect according to the above-described conventional determination device during engine operation, the number of times that the oil level has been detected to exceed the upper limit level is the reference. When the number of times is reached, it is determined that the oil level has risen abnormally. However, when the vehicle equipped with the internal combustion engine repeats acceleration / deceleration, the oil level of the lubricating oil may swell violently. In such a case, even if there is no abnormality, the detected value of the oil level is the upper limit level. Can often be exceeded. As a result, even if it is normal, an erroneous determination that there is an abnormality may be made. As described above, even when an oil level increase abnormality is determined by applying the above-described conventional determination mode, the probability that an erroneous determination is made due to oil level fluctuations has not yet been wiped away.

  Such a problem also occurs when an oil level lowering abnormality is determined. The oil level increase / decrease abnormality also occurs in an internal combustion engine other than a diesel engine that performs DPF regeneration control by post-injection, and the above problem can also occur in such an internal combustion engine. .

  The present invention has been made in view of such circumstances, and a problem to be solved is to determine an oil level abnormality of an internal combustion engine that can accurately determine an oil level abnormality regardless of oil level fluctuations. To provide an apparatus.

  In order to solve the above problems, the oil level abnormality of the internal combustion engine is detected by detecting the oil surface height of the lubricating oil in the oil pan during operation of the engine and determining whether or not the oil oil surface height of the lubricating oil is abnormal. In the invention according to claim 1 as the determination device, the normal time when the oil level height during one trip from when the ignition switch is turned on to when it is turned off is within the normal range is detected. A temporary / normal determination is made based on a comparison with an abnormal time when the oil level is detected to be in the abnormal range. Then, the main determination as to whether there is an abnormality is made based on a comparison between the number of times that the provisional abnormality determination has been made and the number of times that the provisional normality determination has been made.

  In the above configuration, a normal / abnormal provisional determination is performed by comparing the normal time and the abnormal time during one trip, and the abnormality is determined based on a comparison between the number of times the provisional abnormality determination is performed and the number of provisional normality determinations. The main judgment of presence / absence is performed. For this reason, the temporary oil level fluctuation hardly affects the determination result. Therefore, according to the above configuration, the oil level abnormality can be accurately determined regardless of the oil level fluctuation caused by external factors such as acceleration / deceleration of the vehicle and the internal combustion engine and the road surface condition.

  In addition, the main determination of the presence / absence of an abnormality is, as claimed in claim 2, when there is an abnormality when the number of times of provisional abnormality determination is greater than a predetermined abnormality determination value than the number of times of provisional normality determination. A determination can be made to confirm.

  In addition, as described in claim 3, the provisional determination of abnormality / normality includes the number of times the abnormal time reaches the specified count determination value earlier than the normal time reaches the specified count determination value, and the abnormal time This can be done based on a comparison with the number of times that the normal time has reached the prescribed count determination value earlier than the determination value is reached.

  Depending on the engine speed, the pumping amount of the oil pump changes, and the oil level decreases as the pumping amount increases. For this reason, it is desirable that the engine speed when measuring the normal time and the abnormal time for provisional determination is constant. In addition, depending on the temperature of the lubricating oil, its volume changes and the oil level changes. Therefore, it is desirable that the oil temperature when measuring the normal time and the abnormal time for temporary determination is constant. In addition, while running on a slope, the oil level in the oil pan tilts and the detected oil level changes, so the normal time and abnormal time for temporary judgment are counted when the vehicle equipped with the internal combustion engine is running on the slope It is desirable to avoid this. Therefore, as in claim 4, the engine rotational speed is within a specified range, the engine cooling water temperature is within a specified range, and the vehicle on which the internal combustion engine is mounted is not traveling on a slope. More accurate determination can be made by measuring the normal time and the abnormal time on the condition that at least one of the above conditions is satisfied.

  When the engine speed fluctuates, the oil level fluctuates. Therefore, it is desirable to measure the normal time and the abnormal time after the oil level fluctuation has sufficiently subsided. Further, the time from the fluctuation of the engine rotation speed until the oil level fluctuation is calmed becomes longer as the fluctuation of the engine rotation speed at that time increases. For this reason, as described in claim 5, after the fluctuation of the engine rotational speed has occurred and the delay time set according to the magnitude of the fluctuation has elapsed, the normal time and the abnormal time are measured. In addition, it is possible to measure the normal time and the abnormal time in a state where there is little fluctuation of the oil level, and more accurate determination can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows typically the whole structure of one embodiment of this invention. The time chart which shows an example of the control aspect of the embodiment. The flowchart which shows the process sequence of the abnormality determination routine applied to the embodiment.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an internal combustion engine oil level abnormality determination device according to the present invention will be described below in detail with reference to FIGS. Note that the determination apparatus of the present embodiment is applied to a diesel engine that performs regeneration control of DPF by post injection.

  First, the configuration of the present embodiment will be described with reference to FIG. As shown in the figure, the lubricating system of the diesel engine to which the present embodiment is applied is provided with an oil pump 2 that is installed in the lower part of the engine and pumps up lubricating oil from an oil pan 1 in which lubricating oil is stored. Yes. The lubricating oil discharged from the oil pump 2 is returned to the oil pan 1 through the lubricating parts 3 of the engine parts.

  Further, the oil pan 1 is provided with a level gauge 4 for detecting the oil surface height (oil level) of the lubricating oil stored therein. The level gauge 4 is connected to an electronic control unit 5 that controls engine control.

  The electronic control unit 5 includes a central processing unit (CPU) that executes arithmetic processing related to engine control, and a read-only memory (ROM) that stores engine control programs and data. The electronic control unit 5 also includes a random access memory (RAM) that temporarily stores CPU calculation results, detection results of each sensor, etc., and an input / output port (I / O port) that functions as an interface for exchanging signals with the outside. O).

  In addition to the level gauge 4, the input port of the electronic control unit 5 includes a rotational speed sensor 6 for detecting the engine rotational speed NE, a water temperature sensor 7 for detecting the engine cooling water temperature Tw, a vehicle speed sensor 8 for detecting the vehicle speed Veh, An ignition switch 9 or the like is connected. Further, an OMMS lamp 10 is connected to the output port of the electronic control unit 5 to notify an abnormal increase in oil level due to oil dilution through blinking.

  The electronic control unit 5 determines whether or not there is an abnormal increase in oil level due to oil dilution as part of engine control during engine operation. Details of the oil level abnormality determination in the present embodiment will be described below.

  In the present embodiment, during the engine operation, the electronic control unit 5 detects that the oil level is within the normal range by the level gauge 4 (normal time), and the oil level is abnormal by the level gauge 4. The time (abnormal time) that is detected to be within the range is counted. Then, the electronic control unit 5 makes an abnormal / normal provisional determination based on a comparison of normal time and abnormal time during one trip from when the ignition switch 9 is turned on to when it is turned off. In the present embodiment, the provisional determination is performed by the number of times the abnormal time reaches the count determination value earlier than the normal time reaches the count determination value, and the normal time before the abnormal time reaches the count determination value. The determination is made based on a comparison with the number of times the count determination value has been reached.

  These numbers are stored by a number counter. The number counter is set to take an integer value from “−5” to “+5”. Then, “1” is added to the value when the abnormal time reaches the count determination value earlier than the normal time, and “1” is calculated from the value when the normal time reaches the count determination value earlier than the abnormal time. Is manipulated to be subtracted. At the end of the trip, that is, when the ignition switch 9 is turned off, if the number counter is a positive value, a temporary abnormality determination is made, and if it is a negative value, a temporary normality determination is made.

  And in this Embodiment, this determination of the presence or absence of abnormality is performed based on the comparison with the frequency | count that the temporary abnormality determination was made | formed, and the frequency | count that the temporary normal determination was made. Those times are stored by a trip counter. The trip counter is set to take an integer value from “0” to “+2”. The trip counter is operated so that “1” is added to the value when the temporary abnormality determination is made, and “1” is subtracted from the value when the temporary normality determination is made. In the present embodiment, when the number of times that the provisional abnormality determination has been made becomes greater than the number of times that the provisional normality determination has been made by a specified abnormality determination value or more, that is, the value of the trip counter is greater than or equal to the abnormality determination value. When a failure occurs, it is determined that there is an abnormality. Incidentally, in the present embodiment, the value of the abnormality determination value is set to “+2”. The value of the trip counter is stored and held while the ignition switch is turned off, and the value is taken over for the next trip.

  Note that the above-described normal time and abnormal time are measured only during a period in which the specified time condition is satisfied. Here, all the conditions that the engine rotational speed NE is within the specified range, the engine cooling water temperature Tw is within the specified range, and that the engine is not traveling on the slope are all satisfied as a condition for satisfying the timing condition. It is said. In the present embodiment, the electronic control unit 5 determines whether or not the vehicle is traveling on a hill based on a comparison between the vehicle speed Veh and the engine load. In order to carry out such a determination, the vehicle speed Veh needs to be a certain value or more. For this reason, the timekeeping condition also includes that the vehicle speed Veh is equal to or higher than the lowest vehicle speed at which a slope can be determined.

  On the other hand, when the engine speed fluctuates, the oil level fluctuates in the oil pan 1 accordingly. It is desirable that the normal time and the abnormal time are measured while the oil level fluctuation is quiet. Further, the time from the fluctuation of the engine rotation speed until the oil level fluctuation is calmed becomes longer as the fluctuation of the engine rotation speed at that time increases. Therefore, in the present embodiment, the electronic control unit 5 measures the normal time and the abnormal time after the delay time set according to the magnitude of the fluctuation has elapsed after the fluctuation of the engine rotational speed has occurred. Like that. Note that the delay time is set to a longer time as the fluctuation of the engine rotational speed is larger. It should be noted that even when the engine speed is accelerated and decelerated, there is a difference in the occurrence of oil level fluctuations even if the engine speed fluctuation amount is the same. The delay time is obtained in another manner.

  Next, with reference to FIG. 2, the control mode of this embodiment will be described. The figure shows the changes in oil level, timing conditions, abnormal time, normal time, frequency counter and trip counter in three trips.

  As shown in the figure, if the oil level is in the normal range while the timing condition is satisfied, the normal time is increased at a constant rate. Further, if the oil level is in the abnormal range while the timing condition is satisfied, the abnormal time is increased at a constant rate. When the normal time reaches the count determination value at times T1 and T8, the normal time and abnormal time values are cleared to “0”, and “1” is subtracted from the value of the number counter. At times T2, T3, T5, and T6, when the abnormal time reaches the count determination value, the normal time and abnormal time values are cleared to “0”, and “1” is added to the value of the number counter. The

  At the end of the trip at times T4, T7, and T9, a normal / abnormal provisional determination is made based on the value of the number counter at that time. The trip counter value is manipulated according to the result.

For example, at the end of the first trip (time T4), since the number counter is a positive value (“+1”), a temporary abnormality determination is made, and “1” is added to the value of the trip counter.
At the end of the second trip (time T7), since the number counter is a positive value (“+2”), a temporary abnormality determination is made and “1” is added to the value of the trip counter. Thereby, since the value of the trip counter reaches the abnormality determination value (“+2”), the main determination that there is an abnormality is made, and the OMMS lamp 10 blinks in the next trip.

  Further, at the end of the third trip (time T9), since the number counter is a negative value (“−1”), a temporary normal determination is made, and “1” is subtracted from the trip counter value. . Thereby, the value of the trip counter becomes less than the abnormality determination value (“+2”), and therefore, the OMMS lamp 10 is turned off in the next trip.

  Next, the details of the oil level abnormality determination routine applied to this embodiment will be described with reference to FIG. This routine is repeatedly executed at regular intervals by the electronic control unit 5 during engine operation.

  When this routine is started, it is first determined in step S100 whether or not the timing condition is satisfied. If the timekeeping condition is not satisfied (S100: NO), the process proceeds to step S111. If the timing condition is satisfied (S100: YES), the process proceeds to step S101.

  When the process proceeds to step S101, whether or not the engine rotational speed fluctuates is confirmed in step S101. If there is a fluctuation in the engine speed (S101: YES), the delay time is calculated based on the magnitude of the fluctuation in step S102, and then the process proceeds to step S103. On the other hand, if there is no fluctuation in the engine speed (S101: NO), the process proceeds to step S103 as it is.

  When the process proceeds to step S103, in step S103, it is determined whether or not the delay time calculated in step S102 has elapsed after the engine speed has changed. If the delay time has not elapsed (S103: NO), the process proceeds to step S111. If the delay time has elapsed (S103: YES), the process proceeds to step S104.

  In step S104, it is determined whether or not the detected value of the oil level by the level gauge 4 is within the normal range. If the detected value of the oil level is within the normal range (S104: YES), normal time is integrated in step S105, and in subsequent step S106, it is determined whether or not the normal time is equal to or greater than the count determination value. Determined. If the normal time is less than the count determination value (S106: NO), the process proceeds directly to step S112. If the normal time is equal to or greater than the count determination value (S106: YES), the process proceeds to step S107. When the process proceeds to step S107, “1” is added to the value of the number counter in that step S107, and in step S108, the normal time and the abnormal time are reset to “0”, respectively, and then step S112. The process is transferred to.

  On the other hand, if the detected value of the oil level is within the abnormal range (S104: NO), the abnormal time is integrated in step S109, and in subsequent step S110, it is determined whether or not the abnormal time is equal to or greater than the count determination value. Determined. If the abnormal time is less than the count determination value (S109: NO), the process proceeds to step S112 as it is. If the abnormal time is equal to or greater than the count determination value (S109: YES), the process proceeds to step S111. When the process proceeds to step S111, “1” is subtracted from the value of the number counter in step S111, and in step S108, “0” is reset for the normal time and the abnormal time, respectively, and then step S112. The process is transferred to.

  When the process proceeds to step S112, it is determined whether or not the ignition switch 9 is turned off. If the ignition switch 9 is not turned off (S112: NO), the process of this routine is terminated as it is. On the other hand, if the ignition switch 9 is turned off (S112: YES), the operation of the trip counter value according to the value of the number counter at that time is performed in steps S113 to S115. That is, as the value of the trip counter, “1” is added in step S114 if the value of the number counter is positive, and “1” is subtracted in step S115 if it is negative. If the value of the number counter is “0”, the value of the trip counter is held at the current value. In step S116, it is determined whether or not the trip counter value is equal to or greater than the abnormality determination value. If so (S116: YES), blinking of the OMMS lamp 10 in the next trip is instructed in step S117. The

According to the oil level abnormality determination device for an internal combustion engine of the present embodiment as described above, the following effects can be obtained.
(1) In this embodiment, at the end of each trip, an abnormality is detected based on a comparison between a normal time in which the oil level is detected to be within the normal range and an abnormal time in which the oil level is detected to be in the abnormal range. / Temporary judgment of normal is being performed. Then, the main determination of the presence / absence of an abnormality is performed based on a comparison between the number of times that the provisional abnormality determination has been made and the number of times that the provisional normality determination has been made. In this embodiment, based on a comparison between the number of times that the provisional abnormality determination has been made and the number of times that the provisional normality determination has been made, a normal / abnormal provisional determination is made by comparing the normal time and the abnormal time during one trip. To make a final judgment on whether there is an abnormality. For this reason, the temporary oil level fluctuation hardly affects the determination result. Therefore, according to the present embodiment, it is possible to accurately determine the oil level abnormality regardless of oil level fluctuations due to external factors such as acceleration / deceleration of the vehicle or internal combustion engine and road surface conditions.

  (2) In the present embodiment, the normal time and abnormal time are measured, the engine rotational speed is within a specified range, the engine cooling water temperature is within a specified range, and the internal combustion engine is mounted. This is done on the condition that all the vehicles are not traveling on the slope. Therefore, more accurate determination is possible.

  (3) In the present embodiment, the normal time and the abnormal time are measured after the delay time set according to the magnitude of the fluctuation after the fluctuation of the engine rotational speed has occurred. . For this reason, it is possible to measure the normal time and the abnormal time with little fluctuation of the oil level, and more accurate determination can be made.

In addition, the said embodiment can also be changed and implemented as follows.
In the above embodiment, the abnormality determination value is set to “+2”, but the value may be appropriately changed within a range where appropriate determination is possible.

  In the above embodiment, the normal time and the abnormal time are measured after the delay time set in accordance with the magnitude of the fluctuation after the fluctuation of the engine speed has occurred. If the oil level abnormality can be determined with high accuracy, the setting of the delay time may be omitted.

  -In the above embodiment, all that the engine speed is within the specified range, that the engine coolant temperature is within the specified range, and that the vehicle on which the internal combustion engine is mounted is not traveling on the slope. The normal time and the abnormal time were measured on the condition that If it is possible to detect the oil level with sufficient accuracy, one or more of the conditions may be omitted from the timing condition. If necessary for detecting the oil level with sufficient accuracy, another condition may be added to the timing condition.

  In the above embodiment, the number of times the abnormal time reaches the count determination value earlier than the normal time reaches the count determination value, and the normal time becomes the count determination value earlier than the abnormal time reaches the count determination value. Based on the comparison with the number of times reached, temporary / normal determination is made. However, such provisional determination can be performed in other modes as long as it is based on comparison of normal time and abnormal time of each trip. For example, it is also possible to make an abnormal / normal provisional determination based on the ratio of the sum of normal times and the sum of abnormal times for each trip.

  In the above embodiment, when the number of provisional abnormality determinations is greater than the number of provisional abnormality determinations by a specified abnormality determination value or more, the determination that there is an abnormality has been established. As long as it is based on the comparison between the number of times of provisional abnormality determination and the number of provisional normality determinations, the determination of presence of abnormality may be confirmed in other manners, that is, main determination of abnormality or normal may be performed. For example, it is also possible to perform the abnormal / normal main determination based on the ratio of the number of times of temporary abnormality determination and the number of times of temporary normality determination.

  In the above-described embodiment, the case where the determination of the oil level increase abnormality due to the oil dilution has been described, but the determination apparatus of the present invention also performs the determination of the oil level decrease abnormality due to the consumption of the lubricating oil. The same can be applied.

  In the above-described embodiment, the case where the present invention is applied to a diesel engine that performs post-injection DPF regeneration control has been described. However, the determination device of the present invention can be similarly applied to other internal combustion engines.

  DESCRIPTION OF SYMBOLS 1 ... Oil pan, 2 ... Oil pump, 3 ... Lubrication part, 4 ... Level gauge, 5 ... Electronic control unit, 6 ... Rotational speed sensor, 7 ... Water temperature sensor, 8 ... Vehicle speed sensor, 9 ... Ignition switch, 10 ... OMMS lamp.

Claims (5)

In an oil level abnormality determination device for an internal combustion engine that detects an oil level height of lubricating oil in an oil pan during engine operation and determines whether or not there is an abnormality in the oil level height of the lubricating oil,
Detects that the oil level is within the normal range during one trip from when the ignition switch is turned on to when it is turned off. Based on the comparison with the abnormal time that has been made, a temporary determination of abnormality / normal,
An apparatus for determining abnormality in an oil level of an internal combustion engine, wherein the determination of the presence or absence of an abnormality is made based on a comparison between the number of times a provisional abnormality determination has been made and the number of times a provisional normality determination has been made. The main determination of the presence / absence of the abnormality is performed so as to determine the determination that there is an abnormality when the number of times that the provisional abnormality determination has been made is greater than the number of times that the provisional normality determination has been made by a predetermined abnormality determination value The apparatus for determining an abnormality in an oil level of an internal combustion engine according to claim 1. The tentative determination of abnormality / normal includes the number of times the abnormal time reaches a specified count determination value earlier than the normal time reaches a specified count determination value, and the abnormal time reaches the specified count determination value. The apparatus for determining an abnormality in an oil level of an internal combustion engine according to claim 1 or 2, wherein the determination is made based on a comparison with the number of times that the normal time has reached the prescribed count determination value earlier than reaching the specified count determination value. When measuring the normal time and the abnormal time, the engine speed is within a specified range, the engine cooling water temperature is within a specified range, and the vehicle on which the internal combustion engine is mounted is not traveling on a slope. The determination device for abnormality in the oil level of the internal combustion engine according to any one of claims 1 to 3, wherein the determination is made on the condition that at least one of the above is established. The time for measuring the normal time and the abnormal time is performed after a delay time set according to the magnitude of the fluctuation has elapsed since the fluctuation of the engine rotation speed has occurred. An oil level abnormality determination device for an internal combustion engine as described.

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