JP6374331B2 - Engine oil level detector - Google Patents

Description

  The present invention relates to a technical field of an engine oil level detection device that detects an oil level position of engine oil in an oil reservoir such as an oil pan provided in a vehicle.

Japanese Patent Laid-Open No. 5-332120 JP-A-57-84316

  An engine oil level detection device that detects the oil level of an engine oil in an oil storage tank that stores engine oil (lubricating oil) in a circulating manner with the engine, such as an oil pan provided below a vehicle engine, is known. (See, for example, Patent Documents 1 and 2 above).

  Patent Document 1 discloses a technique capable of detecting the oil level position of engine oil not by binary values of Full / Low but by multivalues of three or more values. Specifically, Patent Document 1 discloses a float that floats on an oil surface in an oil tank, and a plurality of reed switches (hereinafter referred to as “oil level switches”) that are arranged in the vertical direction and are turned on when the floats are close to each other. A technique is disclosed that multi-values the oil level position based on the number of oil level switches that are provided and turned on.

  However, providing a plurality of oil level switches is undesirable because it leads to an increase in cost.

  Therefore, the present invention aims to overcome the above-described problems and to reduce the cost of an engine oil level detection device that multi-values the oil level position of the engine oil in the oil storage tank.

  The engine oil level detection device according to the present invention is an engine oil level detection device that detects an oil level position of the engine oil in an oil storage tank that stores the engine oil so as to be circulated with the engine, The oil level switch that is turned on in response to the oil level position reaching a predetermined level, and the time from when the engine is stopped to the time when the oil level switch is turned on are measured and measured. And an oil level estimation unit that estimates the oil level position based on the time.

  Thereby, it is not necessary to provide a plurality of oil level switches for multi-value detection of the engine oil oil level position.

In the engine oil level detection device according to the present invention described above, the oil level estimation unit is a time / oil level representing a correspondence relationship between a time from the reference time point until the oil level switch is turned on and the oil level position. It is desirable to estimate the oil level position based on position correspondence information.
By using the time / oil surface position correspondence information representing the correspondence between the time and the oil surface position as described above, it is possible to estimate the engine oil oil surface position relatively easily.

In the engine oil level detection device according to the present invention described above, the oil level estimation unit is configured to provide information on the oil level position at each time assumed as a time from the reference time point until the oil level switch is turned on. It is desirable to estimate the oil level position based on the time / oil level position correspondence information as table information associated with.
Thereby, the estimation of the engine oil oil level position is realized only by acquiring the oil level position information of the engine oil corresponding to the measurement time from the table information.

In the engine oil level detection device according to the present invention described above, the oil level estimation unit is provided with an operation time until the engine stops, a rotational speed immediately before the engine stop, and the oil storage tank. It is determined whether at least one of the acceleration acting on the vehicle or the temperature of the engine oil deviates from a predetermined assumed value. It is desirable not to perform position estimation.
The operating time until the engine stops, the number of revolutions immediately before the engine stops, the acceleration acting on the vehicle provided with the oil storage tank, or the temperature of the engine oil is the time from the reference time until the oil level switch is turned on. The engine oil level position detection accuracy is improved by not estimating the oil level position when these factors deviate from the assumed values. Reduction can be prevented.

In the engine oil level detection device according to the present invention described above, the oil level estimation unit includes a time from the reference time until the oil level switch is turned on, an operation time until the engine is stopped, the engine The time representing the correspondence relationship of the oil level position to a combination of at least one of the rotational speed immediately before the stop, the acceleration acting on the vehicle provided with the oil storage tank, and the temperature of the engine oil It is desirable to estimate the oil level position based on the oil level position correspondence information.
As a result, the estimation of the engine oil oil level position based on the time from the reference time point until the oil level switch is turned on indicates the correspondence between the time from the reference time point until the oil level switch is turned on and the engine oil oil level position. It is done in a form that takes into account the changing elements.

  According to the present invention, it is not necessary to provide a plurality of oil level switches in the engine oil level detection device that multi-values the oil level position of the engine oil in the oil storage tank, and the cost can be reduced.

It is the block diagram which showed the structure outline | summary of the vehicle control apparatus provided with the engine oil level detection apparatus as embodiment. It is explanatory drawing of an oil level switch. It is explanatory drawing about the oil level detection method of embodiment. It is the figure which showed the example of time and oil level position corresponding | compatible information. It is a flowchart of an oil level detection process. It is the figure which showed the other example of time and oil level position corresponding information. It is a flowchart of the oil level detection process in another example of the detection method.

<1. Overall Configuration of Vehicle Control Device>
FIG. 1 is a block diagram showing an outline of the configuration of a vehicle control device 1 including an engine oil level detection device according to an embodiment of the present invention. In FIG. 1, only the configuration of the main part according to the present invention is extracted and shown from the configuration of the vehicle control device 1.
The engine oil level detection device includes at least the engine control unit 3 and the oil level switch 10d among the components shown in FIG.

  The vehicle control apparatus 1 includes a display control unit 2, an engine control unit 3, a transmission control unit 4, a brake control unit 5, a display unit 6, an engine-related actuator 7, a transmission-related actuator 8, a brake-related actuator 9, and sensors / operators. 10 and a bus 11.

The sensors / operators 10 comprehensively represent various sensors and operators provided on the vehicle. The sensor / operator 10 has a speed sensor 10a that detects the speed of the host vehicle as a vehicle speed, an engine speed sensor 10b that detects the engine speed, and an accelerator opening degree that is detected from the amount of depression of the accelerator pedal. There is an accelerator opening sensor 10c. Also, an oil level switch 10d that is turned on when the level of engine oil Eo that functions as engine lubricating oil reaches a predetermined level, an oil temperature sensor 10e that detects the temperature of engine oil Eo as an oil temperature, and engine cooling There is a water temperature sensor 10f that detects the temperature of water as a water temperature, a G sensor 10g that detects acceleration acting on the host vehicle, and a brake switch 10h that is turned ON / OFF according to operation / non-operation of the brake pedal.
Although not shown, the sensor / operator 10 is provided as another sensor, for example, an intake air amount sensor for detecting the intake air amount to the engine, and is provided in each intake passage and supplied to each cylinder of the engine. A throttle opening sensor that detects the opening of a throttle valve that adjusts the intake air amount, an outside air temperature sensor that detects the temperature outside the vehicle, and the like are also provided.
Further, as an operator, an ignition switch for instructing start / stop of the engine, an automatic transmission mode / manual transmission mode selection in the automatic transmission, and an up / down instruction in the manual transmission mode are given. There are a select lever, a display changeover switch for switching display information in an MFD (Multi Function Display) provided in the display unit 11 described later, and the like.

The oil level switch 10d provided as the sensor / operator 10 will be described with reference to FIG.
The oil level switch 10 d is provided for the oil pan 101 disposed below the engine block 100. The oil pan 101 is an oil storage tank that stores the engine oil Eo so that it can circulate with the engine.
In the oil pan 101, there are provided a rod-shaped guide 101a extending in the vertical direction (height direction) and a float 101b having a ring-shaped outer shape and having the rod-shaped guide 101a inserted through a central cavity. . The float 101b has buoyancy with respect to the engine oil Eo, and is guided by the rod-shaped guide 101a according to the vertical displacement of the oil level Seo of the engine oil Eo stored in the oil pan 101. Displaces vertically.
The oil level switch 10d is a switch that is turned on when the float 101b approaches. That is, the oil level switch 10d is turned on when the level of the engine oil Eo (height of the oil level Seo) reaches a predetermined level (predetermined height).

Returning to FIG.
The display control unit 2, the engine control unit 3, the transmission control unit 4, and the brake control unit 5 are each a micro that includes, for example, a central processing unit (CPU), a read only memory (ROM), and a random access memory (RAM). The computers are connected to each other via a bus 11 so that data communication is possible. The display unit 6, the engine-related actuator 7, the transmission-related actuator 8, and the brake-related actuator 9 are provided as control targets of these control units.

  The display unit 6 comprehensively represents various meters and MFDs such as a speedometer and a tachometer provided in a meter panel installed in front of the driver, and other display devices for presenting information to the driver. ing. Various information such as the total travel distance of the host vehicle, the outside air temperature, and instantaneous fuel consumption can be displayed on the MFD simultaneously or by switching.

  The display control unit 2 displays a display based on a detection signal from a predetermined sensor such as the vehicle speed sensor 10a, the engine speed sensor 10b, or the above-described outside air temperature sensor in the sensor / operator 10 or operation input information by the operator. The display operation by the unit 6 is controlled.

The engine control unit 3 controls various actuators provided as the engine-related actuator 7 based on a detection signal from a predetermined sensor in the sensor / operator 10 or operation input information by the operator. As the engine-related actuator 7, for example, various actuators related to engine driving such as a throttle actuator for driving a throttle valve and an injector for performing fuel injection are provided.
For example, the engine control unit 3 performs engine start / stop control according to the operation of the ignition switch described above. The engine control unit 3 also controls the fuel injection timing, the fuel injection pulse width, the throttle opening, and the like based on detection signals from predetermined sensors such as the engine speed sensor 10b and the accelerator opening sensor 10c.

In addition, the engine control unit 3 in this example performs a process of detecting the level (oil level Seo height) of the engine oil Eo in the oil pan 101 based on the detection information by the oil level switch 10d. Further, the engine control unit 3 transmits the detected level information of the engine oil Eo to the display control unit 2 and causes the display unit 6 to display it.
The oil level detection method will be described later.

The transmission control unit 4 controls various actuators provided as the transmission-related actuator 8 based on a detection signal from a predetermined sensor in the sensor / operator 10 or operation input information by the operator. As the transmission-related actuator 8, for example, an actuator for performing shift control of the automatic transmission is provided.
For example, when the automatic shift mode is selected by the above-described select lever, the transmission control unit 4 performs a shift control by outputting a shift signal to the actuator according to a predetermined shift pattern. Further, when the manual shift mode is set, the transmission control unit 4 performs a shift control by outputting a shift signal according to a shift up / down instruction from the select lever to the actuator.

  The brake control unit 5 controls various actuators provided as the brake-related actuator 9 based on a detection signal from a predetermined sensor in the sensor / operator 10 or operation input information by the operator. As the brake-related actuator 9, for example, various brake-related actuators such as a hydraulic pressure control actuator for controlling the hydraulic pressure output from the brake booster to the master cylinder and the hydraulic pressure in the brake fluid piping are provided. For example, the brake control unit 5 calculates the slip ratio of the wheel from detection information of a predetermined sensor (for example, an axle rotation speed sensor or the vehicle speed sensor 10a), and the hydraulic pressure is controlled by the hydraulic control actuator according to the slip ratio. By so doing, so-called ABS (Antilock Brake System) control is realized.

<2. Overview of oil level detection method>
FIG. 3 is an explanatory diagram of the oil level detection method of the embodiment, and illustrates the relationship between the elapsed time before and after the engine is stopped and the height of the oil level Seo. Specifically, in FIG. 3, for each case where the oil level Seo was Sb1, Sb2, Sb3, Sb4, and Sb5 before the engine stopped (that is, during engine operation), the elapsed time after the engine stopped The transition of the corresponding oil level Seo is shown. Note that the height Sb of the oil level Seo before the engine stops is Sb1>Sb2>Sb3>Sb4> Sb5.

The height of the oil level Seo in the oil pan 101 is relatively low during engine operation when the engine oil Eo is taken out to the engine side. When the engine is stopped, the engine oil Eo begins to gradually return to the oil pan 101, and after a certain time has elapsed since the engine stopped (when the engine oil Eo has almost returned from the engine side), the height of the oil level Seo becomes Stabilize.
In the detection of the level of the engine oil Eo, the level to be detected is a level in a state where the oil level Seo is stable after a certain period of time has elapsed after the engine is stopped. In this example, as an example of multi-level detection of the level of the engine oil Eo, a case where five values of “Full”, “Mid + α”, “Mid”, “Low + α”, and “Low” are detected is illustrated.

  Here, the oil level switch 10d is provided to turn on in response to the level of the engine oil Eo reaching the level represented by “x” in the drawing. In this example, the level x is set to a level that satisfies the condition that it is lower than the “Low” level and higher than the “sb1” level. In other words, it is set to a level lower than the lowest level of the detectable oil level and higher than the oil level during engine operation corresponding to the highest level (“Full”) of the detectable oil levels. doing.

  In the case of “Sb1” where the amount of oil is the largest (that is, in the case of “Full”), the time until the engine oil Eo starts to return from the engine side to the oil pan 101 side and reaches level x after the engine stops is the shortest. (For example, “a seconds”). In the case of other Sb2 to Sb5 (that is, “Mid + α” to “Low”), the level of the engine oil Eo reaches the level x after the engine stops in the order of Sb2, Sb3, Sb4, and Sb5 in which the oil amount is large. (B seconds, “c seconds”, “d seconds”, and “e seconds” in that order).

In the detection method of this example, the time from when the engine stops until the level of the engine oil Eo reaches level x for each level of “Full”, “Mid + α”, “Mid”, “Low + α”, and “Low” that are to be obtained as detection results. That is, the time from when the engine is stopped to when the oil level switch 10d is turned on is ascertained. Specifically, for example, the “Full” level is “˜a seconds”, the “Mid + α” level is “a + 1 to b seconds”, the “Mid” level is “b + 1 to c seconds”, and the “Low + α” level is For “c + 1 to d seconds” and “Low” levels, the time of “d + 1 seconds to” is previously determined by conducting an experiment or the like.
In addition, in the detection method of this example, the time until the oil level switch 10d is turned on is measured based on the stop point of the engine, and “Full” is determined depending on which of the above grasped times the measurement time corresponds to. ”“ Mid + α ”,“ Mid ”,“ Low + α ”, or“ Low ”, an oil level detection result is obtained.

  As described above, in this example, the level x (the level at which the oil level switch 10d is turned on) is set lower than the “Low” level, but according to this, the measurement time is redundant in the detection method described above. Is prevented. Since the detection method of this example is a method realized by performing time measurement after the engine is stopped, the redundant measurement time unnecessarily increases the operation time of the engine control unit 3 after the engine is stopped. It means to end up. By shortening the measurement time by setting the level x described above, the operation time of the engine control unit 3 after the engine is stopped can be shortened, and the waste of electric power can be suppressed.

In order to realize the detection method as described above, the vehicle control apparatus 1 starts the engine oil from the engine stop time for each level of “Full”, “Mid + α”, “Mid”, “Low + α”, and “Low” to be obtained as a detection result. Time / level correspondence information (time / oil surface position correspondence information) I1 in which information on time until the level of Eo reaches level x is associated is stored (see FIG. 4).
The time / level correspondence information I1 is stored in a storage device that can be read by the engine control unit 3, such as the ROM provided in the engine control unit 3, for example.

<3. Processing procedure>
Hereinafter, a specific processing procedure for realizing the oil level detection method as the embodiment whose outline has been described above will be described with reference to the flowchart of FIG. 5.
The process shown in FIG. 5 is executed by the CPU in the engine control unit 3 based on a program stored in a predetermined storage device such as the ROM described above.

  First, the engine control unit 3 stands by until a stop of the engine is detected in step S101, and when a stop of the engine is detected, a time measurement is started in step S102. The detection of engine stop may be detection of an engine stop operation, or may be detection of execution of engine stop control in response to the stop operation.

  The subsequent steps S103 to S106 are processes for determining whether or not a “detection exclusion condition” that is determined in advance as the oil level detection process should not be executed.

First, in step S103, it is determined whether or not the engine operating time until the engine is stopped is equal to or less than a certain time. If an affirmative result is obtained that the engine operating time is equal to or less than the certain time, the process proceeds to step S111. The process shown in this figure is completed after proceeding to reset the time measurement value to zero.
If the engine operating time until the engine stops is an extremely short time such as 10 seconds, for example, whether or not the engine has been operating for a sufficient time before the engine is operating, the influence of the oil temperature condition, etc. Thus, the height of the oil level Seo varies when the engine is stopped. That is, the height of the oil level Seo is not stable depending on the situation before the engine is operating (hereinafter referred to as “previous situation”). Therefore, regardless of the previous situation, the time until the oil level Seo is stabilized is grasped, and when the engine operating time until the engine stops is less than the grasped time, the time measurement is performed as described above. And stop the oil level detection process. This prevents the oil level detection accuracy from being lowered.
The engine operation time is measured by the engine control unit 3 as the time from the start to the stop of the engine.

If a negative result is obtained in step S103 that the engine operating time until the engine is stopped is not less than a certain time, the engine control unit 3 proceeds to step S104, and whether the engine speed immediately before the engine is stopped is outside a certain range. Determine whether or not. If an affirmative result is obtained that the engine speed immediately before the engine stop is outside a certain range, the process proceeds to step S111, the time measurement value is reset to 0, and the process shown in this figure ends.
The higher the engine speed immediately before the engine stops, the lower the oil level Seo (because the amount of oil taken out by the oil pump for supplying the engine oil Eo from the oil pan 101 side to the engine side increases). That is, the time from when the engine is stopped until the oil level switch 10d is turned on becomes longer. Further, depending on the type of engine, the higher the engine speed, the higher the oil aeration rate, and there is a possibility that the time from when the engine is stopped until the oil level switch 10d is turned on may be shortened.
Thus, whether or not the engine speed immediately before engine stop is high is an element that affects the accuracy of oil level detection. Therefore, as described above, it is determined whether or not the engine speed immediately before the engine stops is outside a certain range (for example, whether or not the engine speed is equal to or higher than a predetermined speed), and if a positive result is obtained, time measurement is performed. Stop and do not perform the oil level detection process. This prevents the oil level detection accuracy from being lowered.

  As the engine speed immediately before the engine stop, for example, sampling performed by the engine control unit 3 in a predetermined cycle with respect to the detection signal from the engine speed sensor 10b is set to the sampling timing immediately before the time when the engine stop is detected. A sampled value may be used. Or it is good also as an average value etc. of the value sampled at the multiple sampling timing nearest to the time of the engine stop being detected.

If a negative result is obtained in step S104 that the engine speed immediately before the engine is stopped is not outside the certain range, the engine control unit 3 proceeds to step S105 and determines whether or not the acceleration is outside the certain range. Specifically, it is determined whether or not the value of acceleration detected by the G sensor 10g (respective acceleration acting in the longitudinal direction and lateral direction of the vehicle) is outside a certain range. If an affirmative result is obtained that the acceleration is outside the certain range, the process proceeds to step S111, the time measurement value is reset to 0, and the process shown in this figure is terminated.
For example, when the engine is stopped, the oil level Seo is inclined from the horizontal state depending on the condition of the road surface on which the host vehicle is stopped (for example, the gradient). That is, the oil level switch 10d is turned on even though the oil level in the horizontal state is lower than the level x, or conversely, the oil level in the horizontal state is higher than the level x. The level switch 10d is not turned on, and the oil level detection accuracy is lowered.
For this reason, as described above, it was determined whether or not the acceleration was out of a certain range (for example, whether or not both the longitudinal and lateral accelerations were ± 0.1 m / s ² ), and a positive result was obtained. In this case, the time measurement is stopped and the oil level detection process is not performed. This prevents the oil level detection accuracy from being lowered.

If a negative result is obtained in step S105 that the acceleration is not outside the certain range, the engine control unit 3 proceeds to step S106, and whether the oil temperature value detected by the oil temperature sensor 10e is outside the certain range. Determine whether or not. If an affirmative result is obtained that the oil temperature is outside the certain range, the process proceeds to step S111, the time measurement value is reset to 0, and the process shown in FIG.
Since the engine oil Eo expands thermally, the higher the oil temperature, the higher the oil level Seo, and the shorter the time until the oil level switch 10d is turned on. When the oil temperature is low, the kinematic viscosity of the engine oil Eo is high, the speed at which the engine oil Eo supplied to each part in the engine returns to the oil pan 101 side is slow, and the time until the oil level switch 10d is turned on. Tends to be longer.
If the oil temperature is excessively high and excessively low, it should be set for each level of “Full” to “Low” to be detected (time until the oil level switch 10d is turned on). ) Is wide and accurate detection may not be possible. For this reason, as described above, it is determined whether or not the value of the oil temperature is out of a certain range. If a positive result is obtained, the time measurement is stopped and the oil level detection process is not performed. This prevents the oil level detection accuracy from being lowered.

If a negative result is obtained in step S106, that is, if it is determined that all the “detection exclusion conditions” in steps S103 to S106 are not satisfied, the engine control unit 3 proceeds to step S107, and the oil level switch 10d is turned on. Wait until
If the oil level switch 10d is turned on, the time measurement is stopped in step S108, and the process proceeds to step S109. The oil level corresponding to the measurement time is acquired based on the time / level correspondence information I1. Specifically, if the measurement time corresponds to “˜a seconds”, the “Full” level is set. If the measurement time corresponds to “a + 1 to b seconds”, the “Mid + α” level is set. If the measurement time corresponds to “b + 1 to c seconds”, “ If the “Mid” level corresponds to “c + 1 to d seconds”, the “Low + α” level is acquired, and if it corresponds to “d + 1 seconds to”, the “Low” level is acquired.
In other words, the corresponding oil level (oil surface position) is estimated based on the measurement time, and the estimated oil level is obtained as a detection result.

  When the corresponding oil level is acquired in step S109, the engine control unit 3 stores the acquired oil level information in step S110. That is, the oil level information is stored in a storage device that can be read by the engine control unit 3 so that the detected oil level information can be presented to the driver at the next engine start. Note that the storage device that stores information in step S110 is a non-volatile storage device or a volatile storage device in which power supply is continued even when the engine is stopped.

  When the oil level information is stored in step S110, the engine control unit 3 resets the time measurement value to 0 in step S111 and ends the processing shown in this figure.

In the above, an example is given in which the time measurement until the oil level switch 10d is turned on is immediately started according to the engine stop by the time measurement start process in step S102. However, the time measurement start process in step S102 is For example, the determination processing in steps S103 to S106 may be performed (that is, in response to a negative result obtained in step S106 ) . In this case, the reference point in time measurement does not exactly match the engine stop point, but the time until the oil level switch 10d is turned on is based on the point in time when the engine is stopped. It is only necessary to start from a predetermined reference time, and it is not always necessary to exactly match the engine stop time.

  In the above description, the oil temperature condition is cited as one of the “detection exclusion conditions” (S106). However, since the oil temperature and the water temperature have a correlation, the water temperature can be used instead of the oil temperature. At this time, in order to ensure detection accuracy of the oil level, the relationship between the water temperature and the oil temperature may be grasped, and the “constant range” corresponding to the water temperature may be set as the “constant range” in step S106.

  Furthermore, in the above description, it is assumed that the oil level is detected while the host vehicle is stopped. However, in the case of a hybrid vehicle, the engine may stop even during traveling. It is also conceivable to perform time measurement based on the stop time point and estimate the oil level based on the measurement time. During traveling, acceleration of the vehicle, front / rear and left / right acceleration may occur due to the occurrence of rolls during acceleration / deceleration of the vehicle, traveling on a curve, and the like, which may cause a decrease in detection accuracy. Therefore, it is effective to provide a detection exclusion condition determination process based on acceleration as in step S103.

<4. Another example of detection method>
In the above, an example in which the oil level is not detected when the “detection exclusion condition” is satisfied has been described. Hereinafter, as another example of the detection method, a method that enables oil level detection even in a case that satisfies the “detection exclusion condition” will be described.
Hereinafter, as an example, a method that enables oil level detection even when the oil temperature satisfies the “detection exclusion condition” will be described.

FIG. 6 shows an example of the time / level correspondence information I2 used in another example of the detection method.
As shown in the figure, the time / level correspondence information I2 includes the “Full”, “Mid + α”, “Mid”, “Low + α”, and “Low” levels to be obtained as detection results, and the time from when the engine stops until the oil level switch 10d is turned on. The correspondence with time information is defined as information defined for each oil temperature. Such time / level correspondence information I2 can be regarded as information prepared for each oil temperature with the time / level correspondence information I1 shown in FIG. In creating the time / level correspondence information I2, the correspondence between each level and time for each oil temperature is obtained in advance through experiments or the like.
FIG. 6 shows an example in which the correspondence between each level and time is defined every 20 ° C. In this case, the oil level at the oil temperature that is not defined in the time / level correspondence information I2 may be estimated using information defined in the time / level correspondence information I2. As an example, when detecting the oil level when the oil temperature not defined in the time / level correspondence information I2 = 15 ° C., the oil temperature defined in the time / level correspondence information I2 = The time information is corrected according to the temperature difference between 15 ° C. and 20 ° C., and the oil level information corresponding to the measurement time is acquired based on the corrected time information.
Of course, as the time / level correspondence information I2, information on correspondence between time and level may be prepared for each 1 ° C. of the oil temperature, and in that case, estimation from the definition information as described above is unnecessary. it can.

  In addition, it can be said that the time / level correspondence information I2 as described above is the following information. That is, the information represents the correspondence relationship between the oil level (oil level position) of the engine oil Eo with respect to the combination of the time from when the engine is stopped to when the oil level switch 10d is turned on and the oil temperature.

The flowchart in FIG. 7 shows a specific processing procedure to be executed in another example of the detection method. In FIG. 7, processes similar to those already described so far are denoted by the same step numbers and description thereof is omitted.
In this case, the process of step S106 is omitted, and the engine controller 3 detects the oil temperature detected by the oil temperature sensor 10e as the oil temperature acquisition process of step S201 in response to stopping the time measurement in step S108. Process to acquire the information of.
Then, in step S202, the engine control unit 3 acquires an oil level corresponding to the measurement time based on the time / level correspondence information I1 selected according to the oil temperature.

  Also in this case, after acquiring the oil level, the engine control unit 3 executes the oil level storing process in step S110, and then performs the time measurement value 0 reset process in step S111, and ends the oil level detection process.

  The same processing can be performed for the “detection exclusion condition” elements other than the oil temperature. Specifically, the time / level correspondence information I1 is similarly prepared for each element value of the engine operating time until the engine is stopped, the engine speed immediately before the engine is stopped, and the acceleration. At the time of level detection, the time / level correspondence information I1 that matches the value of the corresponding element is selected, and the oil level corresponding to the measurement time may be acquired based on the selected time / level correspondence information I1.

In addition, the oil level can be detected in consideration of all factors of the engine operating time until the engine is stopped, the engine speed immediately before the engine is stopped, the acceleration, and the oil temperature. In that case, for each combination of values of these elements (that is, for each combination of engine operating time = xx seconds, engine speed = ΔΔ rpm, acceleration = OO m / s ² , oil temperature = □□ ° C.) B), the correspondence between the oil level and the time from when the engine stops until the oil level switch 10d is turned on, and the oil level based on the measured time using the time / level correspondence information that defines the correspondence May be estimated (detected).

Here, including the above “another example of the detection method”, the description so far has exemplified the case where table information is used as the “time / level correspondence information” used for estimating the oil level based on the measurement time. The estimation of the level can also be performed based on a function representing a correspondence relationship between the oil level and the time from the reference time point when the engine is stopped as a reference until the oil level switch is turned on.
By using the time / level correspondence information as such a function, the detected value of the oil level can be obtained as a linear value instead of a stepwise value such as “Full” to “Low”.

In the above “another example of the detection method”, such functions include the engine operation time until the engine stop exemplified as the “detection exclusion condition” element, the engine speed immediately before the engine stop, the acceleration, or the oil A function is prepared in consideration of at least one element of the temperature, in other words, at least one element among the elements that change the correspondence relationship between the oil level and the time until the oil level switch 10d is turned on. That is, for example, in the case of an oil temperature element, a function is prepared that represents the correspondence relationship between the oil level of the engine oil Eo and the combination of the time until the oil level switch 10d is turned on and the oil temperature. Specifically, it is a function that is generated so that the oil level is obtained using, for example, the time until the oil level switch 10d is turned on and the oil temperature as variables.
The function (and the table information exemplified as the time / level correspondence information I2) used in such “another example of the detection method” can be expressed as the following information. That is, the engine oil Eo with respect to a combination of the time from when the engine is stopped until the oil level switch 10d is turned on and at least one of the engine operating time until the engine stops, the engine speed immediately before the engine stops, the acceleration, or the oil temperature. This is information that shows the correspondence between oil levels.

<5. Summary of Embodiment>
As described above, the engine oil level detection device of the embodiment detects the oil level position of the engine oil in the oil storage tank (oil pan 101) that stores the engine oil (Eo) so as to be able to circulate with the engine. An engine oil level detection device, an oil level switch (10d) that is turned on in response to the oil level position reaching a predetermined level (level x), and a reference time point based on when the engine is stopped And an oil level estimation unit (engine control unit 3) for measuring the time from when the oil level switch is turned on to estimating the oil level position based on the measured time.

Thereby, it is not necessary to provide a plurality of oil level switches for multi-value detection of the engine oil oil level position.
Therefore, it is possible to reduce the cost of the engine oil level detection device that multi-detects the oil level of the engine oil in the oil storage tank.

Further, in the engine oil level detection device according to the embodiment, the oil level estimation unit includes time / oil level position correspondence information representing a correspondence relationship between the time from the reference time point until the oil level switch is turned on and the oil level position. The oil level position is estimated based on (time / level correspondence information I1 or I2).
By using the time / oil surface position correspondence information representing the correspondence between the time and the oil surface position as described above, it is possible to estimate the engine oil oil surface position relatively easily. Specifically, for example, if the table information as described above is used as the time / oil level position correspondence information, it is possible to eliminate the calculation process in estimating the oil level position. The oil level position can be easily estimated by substituting the measurement time into the function.
Therefore, it is possible to reduce the processing load required for detecting the oil level of the engine oil.

Further, in the engine oil level detection device according to the embodiment, the oil level estimation unit associates the oil level position information with each time assumed as the time from the reference time point until the oil level switch is turned on. The oil level position is estimated based on time / oil level position correspondence information as table information.
Thereby, the estimation of the engine oil oil level position is realized only by acquiring the oil level position information of the engine oil corresponding to the measurement time from the table information.
Therefore, it is possible to reduce the processing load required for detecting the oil level of the engine oil.

In the engine oil level detection device according to the embodiment, the oil level estimation unit acts on the vehicle provided with the operating time until the engine stops, the rotation speed immediately before the engine stops, and the oil storage tank. It is determined whether or not at least one of the acceleration and the temperature of the engine oil deviates from a predetermined assumed value, and if it deviates from the assumed value, the oil level position is not estimated. Yes.
The operating time until the engine stops, the number of revolutions immediately before the engine stops, the acceleration acting on the vehicle provided with the oil storage tank, or the temperature of the engine oil is the time from the reference time until the oil level switch is turned on. The engine oil level position detection accuracy is improved by not estimating the oil level position when these factors deviate from the assumed values. Reduction can be prevented.

Furthermore, in the engine oil level detection device of the embodiment, the oil level estimation unit includes the time from the reference time until the oil level switch is turned on, the operation time until the engine is stopped, and the rotation immediately before the engine is stopped. The oil level is based on the time / oil level position correspondence information indicating the relationship of the oil level position to the combination of the number, the acceleration acting on the vehicle provided with the oil storage tank, and / or the temperature of the engine oil. Estimating the position.
As a result, the estimation of the engine oil oil level position based on the time from the reference time point until the oil level switch is turned on indicates the correspondence between the time from the reference time point until the oil level switch is turned on and the engine oil oil level position. It is done in a form that takes into account the changing elements.
Therefore, it is possible to improve the detection accuracy of the engine oil oil level position.

<6. Modification>
Although the embodiments of the present invention have been described above, the present invention is not limited to the specific examples described above, and various modifications can be considered.
For example, in the above, the case where the execution subject of the process according to the present invention is the engine control unit 3 is illustrated, but at least a part of the process according to the present invention is a control unit (ECU) other than the engine control unit 3 : The Electronic Control Unit) is not limited to the above example.

  Moreover, although the case where this invention was applied to the vehicle was illustrated above, this invention is widely applicable to objects, such as a vehicle mounted with an engine.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle control apparatus, 3 ... Engine control part, 10b ... Engine speed sensor, 10d ... Oil level switch, 10e ... Oil temperature sensor, 10f ... Water temperature sensor, 101 ... Oil pan, Eo ... Engine oil, Seo ... Oil level

Claims (5)

An engine oil level detection device that detects an oil level position of the engine oil in an oil storage tank that circulates engine oil between the engine oil,
An oil level switch that is turned on in response to the oil level position reaching a predetermined level;
An oil level estimating unit that measures a time from a reference time point when the engine is stopped to a time when the oil level switch is turned on, and estimates the oil level position based on the measured time. Oil level detection device. The oil level estimator is
2. The engine oil level according to claim 1, wherein the oil level position is estimated based on time / oil level position correspondence information representing a correspondence relationship between a time from the reference time point until the oil level switch is turned on and the oil level position. Detection device. The oil level estimator is
The oil level based on the time-oil level position correspondence information as table information in which the information on the oil level position is associated with each time assumed as the time from the reference time point until the oil level switch is turned on. The engine oil level detection device according to claim 2, wherein the position is estimated. The oil level estimator is
At least one of an operation time until the engine is stopped, a rotational speed immediately before the engine is stopped, an acceleration acting on a vehicle provided with the oil storage tank, and a temperature of the engine oil is determined in advance. The engine oil level according to any one of claims 1 to 3, wherein it is determined whether or not the estimated value is deviated, and the oil level position is not estimated when deviating from the assumed value. Detection device. The oil level estimator is
The time until the oil level switch is turned on from the reference time point, the operation time until the engine is stopped, the rotational speed immediately before the engine is stopped, and the vehicle provided with the oil storage tank The oil level position is estimated based on the time / oil level position correspondence information representing a correspondence relationship of the oil level position to a combination of at least one of acceleration and / or engine oil temperature. 3. The engine oil level detection device according to any one of 3 above.

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