JP2009103630A - Liquid membrane thickness measurement device and controller for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid membrane thickness measurement device, capable of measuring the thickness of liquid membrane with high accuracy, using the fluorescent phenomena of the liquid membrane capable of preferably being used for an internal combustion engine. <P>SOLUTION: The liquid membrane thickness measurement device includes a light-emitting element for emitting ultraviolet light; a half mirror for transferring the ultraviolet light emitted from the light-emitting element and reflecting the light containing the fluorescent light from the liquid membrane side; an optical fiber for transferring the ultraviolet light passed through the half mirror, from the light-emitting element to the liquid membrane and transferring the light, including the fluorescent light emitted from the liquid membrane to the half mirror side; an ultraviolet light cut filter for only passing the fluorescent light from the light, including the fluorescent light reflected by the half mirror; and a light sensor for detecting the intensity of the fluorescent light of the liquid membrane, by receiving the fluorescent light that has passed through the ultraviolet light cut filter and also outputting the voltage value corresponding to the intensity of the fluorescent of the liquid membrane. Each of those constituent elements is accommodated in one cabinet. Thus, the liquid membrane thickness measurement device capable of calculating the thickness of the liquid membrane using the outputting voltage of the optical sensor can be obtained. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid film thickness measuring device that measures the thickness of a liquid film using a fluorescence phenomenon of the liquid film, and to a control device for an internal combustion engine using the liquid film thickness measuring device.

  In recent years, attention has been focused on a technique for irradiating an oil film mixed with a fluorescent material with laser light or the like and measuring the thickness of the oil film based on the intensity of fluorescence emitted from the excited fluorescent material. Here, it is known that the intensity of fluorescence is proportional to the thickness of the oil film.

  For example, Patent Documents 1 to 4 describe techniques for measuring the thickness of an oil film using such a technique and techniques related thereto.

  In Patent Document 1, by irradiating the lubricating oil interposed between a cylinder provided with a light-transmitting portion made of a light-transmitting material and a piston disposed in the cylinder, laser light is applied, There is described an oil film thickness measuring device capable of two-dimensionally measuring the thickness of the lubricating oil based on the fluorescence intensity of the fluorescent substance in the lubricating oil excited by the laser light.

  Patent Document 2 describes an oil film thickness measuring device capable of measuring the thickness of an oil film formed on a sliding surface of a bearing body using the above-described technique. Patent Document 3 describes an oil film thickness measuring method capable of measuring the thickness of an oil film formed between a piston ring and a cylinder wall.

  Patent Document 4 discloses an oil film thickness calibration apparatus that can more accurately measure the oil film thickness during calibration of fluorescence and oil film thickness in oil film thickness measurement using a fluorescence phenomenon.

  In Patent Document 5, the amount of fuel adhering to the inner wall surface is calculated based on each detected value from a plurality of fuel detecting means disposed on the inner wall surface of the intake pipe, and The current fuel deposition change amount is calculated from the current fuel deposition amount calculated based on each detected value and the previous fuel deposition amount, and the basic fuel injection amount determined according to the operating state of the engine is further calculated. A fuel injection control device for an internal combustion engine that determines the next fuel injection amount by correcting based on the amount of change in adhesion is described. Here, each fuel detection means has a pair of electrodes disposed on the inner wall surface of the intake pipe and set to be separated from each other by a predetermined distance, and each detection value from each fuel detection means is between each electrode. It changes according to the amount of fuel adhering.

JP-A-6-174431 JP 2003-247812 A JP 2006-337179 A JP 2004-101209 A Japanese Patent Laid-Open No. 2003-332051

  Using the oil film thickness measurement method described above, the thickness of the fuel adhering to the wall surface of the internal combustion engine (for example, the inner wall surface of the intake pipe) is measured, and the amount of fuel adhering is calculated based on the measurement result. Further, the fuel injection amount of the internal combustion engine can be controlled based on the calculated fuel adhesion amount.

  However, when the oil film thickness measuring device described in the above-mentioned patent document is mounted on an internal combustion engine, the following problem is considered as an example.

  For example, the oil film thickness measurement (measurement) devices described in Patent Documents 1 and 2 described above have a large system configuration as a measurement system, and accordingly, the cost of the oil film thickness measurement (measurement) device increases. There is a problem such as.

  In addition, the oil film thickness measuring device of Patent Document 1 described above has a deep color as a test device such as a cylinder made of a light-transmitting material, and is not feasible for mounting in an internal combustion engine (actual machine). There are challenges. That is, Patent Document 1 does not discuss the system configuration of the oil film thickness measuring device in consideration of mounting on an actual machine.

  Further, in the oil film thickness measuring (measuring) apparatus described in Patent Documents 1 and 2, since the fluorescent material (fluorescent agent) is mixed in the lubricating oil, the lubricating oil (medium as a measurement object) is thereby obtained. ) There is a problem that the physical properties may be changed.

  The present invention has been made in view of the above points, and a liquid film thickness measuring device that measures the thickness of a liquid film with high accuracy using the fluorescence phenomenon of the liquid film, and the liquid film thickness measuring device. An object of the present invention is to provide a control device for an internal combustion engine to which is applied.

  In one aspect of the present invention, a liquid film thickness measuring device that measures the thickness of the liquid film based on the intensity of fluorescence emitted from the liquid film by irradiating the liquid film with ultraviolet light emits the ultraviolet light. A light emitting element that transmits the ultraviolet light from the light emitting element and reflects the light containing the fluorescence from the liquid film, and directs the ultraviolet light transmitted through the half mirror toward the liquid film And transmitting the light containing the fluorescence emitted from the liquid film toward the half mirror, and cutting the ultraviolet light from the light containing the fluorescence reflected by the half mirror. An ultraviolet light cut filter that transmits only the fluorescence, and the fluorescence that has passed through the ultraviolet light cut filter is received to detect the intensity of the fluorescence of the liquid film, and the detected fluorescence intensity Comprising an optical sensor for outputting a voltage value Flip, the.

  The liquid film thickness measuring device measures the thickness of the liquid film based on the intensity of fluorescence emitted from the liquid film by irradiation of the liquid film with ultraviolet light. The liquid film thickness measuring device includes a light emitting element, a half mirror, an optical fiber, an ultraviolet light cut filter, and an optical sensor.

  The light emitting element is, for example, a light emitting diode element, and emits ultraviolet light. The half mirror transmits ultraviolet light emitted from the light emitting element and reflects light including fluorescence emitted from the liquid film side. The optical fiber has an optical path for transmitting light including ultraviolet light and fluorescence, and transmits and irradiates the ultraviolet light from the light emitting element that has passed through the half mirror toward the liquid film, and is emitted from the liquid film. Light including fluorescence is transmitted and irradiated toward the half mirror. In a preferred example, one end of the optical fiber is disposed at a position capable of receiving ultraviolet light from the light emitting element that has passed through the half mirror, and the other end of the optical fiber is the light receiving element. The ultraviolet light is disposed at a position where it can be transmitted toward the liquid film. The ultraviolet light cut filter cuts ultraviolet light from the light including the fluorescence reflected by the half mirror and transmits only the fluorescence. The optical sensor receives the fluorescence transmitted through the ultraviolet light cut filter, detects the fluorescence intensity of the liquid film based on the amount of the received light, and outputs a voltage value corresponding to the detected fluorescence intensity of the liquid film. . Here, the relationship between the output voltage value from the optical sensor and the thickness of the liquid film is generally proportional. Therefore, it is possible to calculate the thickness of the liquid film based on the output voltage value from the optical sensor.

  In one aspect of the liquid film thickness measuring apparatus, the optical fiber is 1, and is emitted from the liquid film, an optical path for transmitting ultraviolet light from the light emitting element toward the liquid film, and The optical path for transmitting the light containing the fluorescence toward the half mirror is constituted by one optical path of the one optical fiber. According to this aspect, the liquid film thickness measuring device can be made more compact as compared with a configuration in which light including ultraviolet light and fluorescence is transmitted using a plurality of optical fibers. The cost of the measuring device can be reduced.

  In another aspect of the liquid film thickness measuring apparatus, the light emitting element, the half mirror, the ultraviolet light cut filter, and the optical sensor are housed in one housing. Thereby, a liquid film thickness measuring apparatus can be made compact. Therefore, in addition to preventing an increase in the cost of the liquid film thickness measuring device, the degree of mounting on an internal combustion engine (actual machine) can be increased.

  In another aspect of the liquid film thickness measuring apparatus, the apparatus further includes an optical path switching device having a mirror including a reflecting surface that reflects received light, and a motor that controls a rotation angle of the mirror. In the periphery, one end of the plurality of optical fibers is arranged at an appropriate interval, and the other end of the plurality of optical fibers is arranged in each of the plurality of measurement portions of the liquid film, The motor reflects the ultraviolet light from the light emitting element side that has passed through the half mirror toward the optical path on the one end side of the optical fiber among the plurality of optical fibers by the reflecting surface of the mirror. And the light containing the fluorescence emitted from the liquid film side through the optical path of the other end of the optical fiber is on the half mirror side by the reflecting surface of the mirror. Controlling the rotation angle of the mirror to be reflected.

  In this aspect, the optical path switching device further includes a mirror including a reflection surface that reflects the received light, and a motor that controls the rotation angle of the mirror. Around the mirror, one end of a plurality of optical fibers is arranged at an appropriate interval, and the other end (tip) of the plurality of optical fibers is arranged at a plurality of measurement portions of the liquid film, respectively. Has been. The motor is configured so that the ultraviolet light from the light emitting element side that has passed through the half mirror is reflected toward the optical path on one end side of any one of the plurality of optical fibers by the reflecting surface of the mirror, and the liquid film The rotation angle of the mirror is controlled so that the light containing fluorescence emitted from the side through the optical path of one end of the optical fiber is reflected to the half mirror side by the reflecting surface of the mirror. That is, in this aspect, by switching the rotation angle of the mirror through the motor of the optical path switching device, the optical path of the optical fiber to be measured among the plurality of optical fibers is switched. This makes it possible to measure the thickness of the liquid film at a plurality of locations.

  In another aspect of the present invention, a control device for an internal combustion engine including the above-described liquid film thickness measuring device can be configured. This makes it possible to measure the thickness of a liquid film (for example, a thin film fuel or a fuel thin film; the same applies hereinafter) attached to the wall surface of the internal combustion engine. In addition, since the liquid film thickness measuring device has a compact configuration as described above, it can be used as a feedback sensor that contributes to space saving of the internal combustion engine.

  In one aspect of the control device for an internal combustion engine, the liquid film thickness measurement device uses a voltage value from the optical sensor obtained in a reference state before fuel injection during cranking of the internal combustion engine as the voltage value. The reference voltage value at which the thickness of the liquid film is zero is used. Based on this reference voltage value, the thickness of the liquid film can be calculated more accurately even when a disturbance occurs in the internal combustion engine.

  In another aspect of the control device for an internal combustion engine described above, a fuel introduction path through which fuel as a component of the liquid film is introduced, and a liquid film thickness conversion means for calculating the thickness of the liquid film per unit fluorescence intensity; The fuel introduction path has a specified thickness portion having a specified thickness, and the intensity of the fluorescence emitted from the fuel in the specified thickness portion by the irradiation of the ultraviolet light is equal to the specified thickness. Detected by the optical sensor through the optical fiber provided in the portion, the liquid film thickness conversion means is configured to detect the prescribed thickness in the prescribed thickness portion and the prescribed thickness portion detected by the optical sensor. Based on the fluorescence intensity, the thickness of the liquid film per unit fluorescence intensity is calculated.

  In this aspect, a fuel introduction path through which fuel as a component of the liquid film is introduced, and a liquid film thickness conversion unit that calculates the thickness of the liquid film per unit fluorescence intensity are provided. The fuel introduction path has a defined thickness portion having a defined thickness. The intensity of the fluorescence emitted from the fuel of the specified thickness portion by the irradiation of the ultraviolet light is detected by the optical sensor through the optical fiber provided in the specified thickness portion. The liquid film thickness conversion means calculates the thickness of the liquid film per unit fluorescence intensity based on the prescribed thickness in the prescribed thickness portion and the fluorescence intensity in the prescribed thickness portion detected by the optical sensor. . The thickness of the liquid film adhering to the wall surface of the internal combustion engine can be calculated more accurately by using the thickness of the liquid film per unit fluorescence intensity thus calculated.

  In another aspect of the control device for an internal combustion engine, the control device includes a cylinder, and an intake valve and an exhaust valve provided corresponding to the cylinder, and the liquid film thickness measuring device is configured to measure an intake stroke in the cylinder. During the period in which the intake valve and the exhaust valve are closed after completion, the thickness of the liquid film adhering to the wall surface of the internal combustion engine in the cycle from the intake stroke to the exhaust stroke is measured.

  In this aspect, a cylinder (cylinder) and an intake valve and an exhaust valve provided corresponding to the cylinder are provided. The liquid film thickness measuring device is a liquid film that adheres to the wall surface of an internal combustion engine in a cycle from the intake stroke to the exhaust stroke during a period in which the intake valve and exhaust valve after the intake stroke in the cylinder are closed. Calculate the thickness. Thereby, the thickness of the liquid film can be calculated for each cycle.

  In another aspect of the control device for an internal combustion engine, a liquid film thickness-liquid film adhesion amount conversion map for converting the thickness of the liquid film into an adhesion amount of the liquid film, and the wall surface of the internal combustion engine Liquid film adhesion amount calculating means for calculating the adhesion amount of the liquid film adhering to the liquid film, and the liquid film adhesion amount calculation means includes a thickness of the liquid film adhering to the wall surface of the internal combustion engine, Based on the liquid film thickness-liquid film adhesion amount conversion map, the adhesion amount of the liquid film is calculated.

  In this aspect, the liquid film thickness-liquid film adhesion amount conversion map for converting the liquid film thickness to the liquid film adhesion amount, and the liquid film adhesion amount to be attached to the wall surface of the internal combustion engine are calculated. Liquid film adhesion amount calculation means. The liquid film adhesion amount calculating means calculates the adhesion amount of the liquid film based on the thickness of the liquid film adhering to the wall surface of the internal combustion engine and the liquid film thickness-liquid film adhesion amount conversion map. By calculating the adhesion amount of the liquid film in this way, the fuel injection control of the internal combustion engine can be performed with high accuracy.

  In another aspect of the control device for an internal combustion engine, the injection amount for determining the fuel injection amount increase coefficient for the cylinder based on the reference injection amount increase coefficient and the correction coefficient for the fuel for the cylinder Increment coefficient determining means, in-cylinder inflow amount calculation means for calculating the inflow amount of the fuel per one fuel injection into the cylinder, and correction coefficient calculation for calculating the correction coefficient Means for calculating in-cylinder inflow per injection when the internal combustion engine is in transition, the liquid film adhesion amount corresponding to the current cycle calculated by the liquid film adhesion amount calculation means And an inflow amount of the fuel per one fuel injection based on a difference between the liquid film adhesion amount corresponding to the previous cycle calculated by the liquid film adhesion amount calculation unit, Correction coefficient calculation The stage calculates the correction coefficient so that the calculated inflow amount of the fuel per one fuel injection becomes a reference inflow amount of the fuel into the cylinder, and the injection amount increase coefficient determining means Determines the fuel injection amount increase coefficient in the next cycle based on the calculated correction coefficient and the reference injection amount increase coefficient.

  In this aspect, the injection amount increase coefficient determining means for determining the fuel injection amount increase coefficient for the cylinder based on the reference injection amount increase coefficient for the cylinder and the correction coefficient, In-cylinder inflow amount calculation means for calculating the inflow amount of fuel per fuel injection, and correction coefficient calculation means for calculating a correction coefficient. Then, during the transition of the internal combustion engine, the in-cylinder inflow amount calculation means per injection includes the liquid film adhesion amount corresponding to the current cycle calculated by the liquid film adhesion amount calculation means, and the liquid film adhesion amount calculation means. The flow rate of the fuel per one fuel injection is calculated based on the difference from the liquid film adhesion amount corresponding to the previous cycle calculated by the correction coefficient calculating means. The correction coefficient is calculated so that the fuel inflow amount per fuel injection becomes the reference inflow amount of fuel into the cylinder, and the injection amount increase coefficient determining means is based on the calculated correction coefficient and the reference injection amount increase coefficient. Thus, the fuel injection amount increase coefficient for the next cycle is determined. As a result, during the transient operation of the internal combustion engine (particularly during the transient operation when the internal combustion engine is cold), highly accurate fuel injection is performed, and at the same time, particulate matter (smoke), nitrogen oxide (NOx), and carbonization are performed. It is possible to suppress a large amount of hydrogen (HC) or the like from being discharged into the atmosphere, and it is possible to reduce emissions.

  Hereinafter, various preferred embodiments of the present invention will be described with reference to the drawings.

[First embodiment]
(Configuration of liquid film thickness measuring device)
First, with reference to FIG. 1 etc., the structure of the liquid film thickness measuring apparatus which concerns on 1st Embodiment of this invention is demonstrated.

  FIG. 1 is a cross-sectional view schematically showing a configuration of a liquid film thickness measuring apparatus 20 according to the first embodiment.

  The liquid film thickness measuring apparatus 20 according to the first embodiment is an apparatus that measures the thickness F of the liquid film 12 based on the intensity of the fluorescence 11 emitted from the liquid film 12 by the irradiation of the ultraviolet light 8 on the liquid film 12. The optical system main body 20x and the optical fiber 5 joined or connected to the optical system main body 20x are mainly provided. In the present specification, the liquid film 12 refers to a thin-film liquid (for example, a fuel containing an additive) that emits fluorescence when excited by irradiation with ultraviolet light. The optical system body 20x includes a housing 1, a light emitting element 2, a half mirror 3, a coupling (joining member) 4, an optical fiber 5, an ultraviolet light cut filter (ultraviolet light absorption filter) 6, and an optical sensor. 7.

  The casing 1 has a shape in which, for example, a first casing 1a having a cylindrical shape and a second casing 1b having a cylindrical shape are coupled in a T shape, and the light emitting element 2 and the half The mirror 3, the ultraviolet light cut filter 6, and the optical sensor 7 are accommodated.

  The light emitting element 2 is disposed on one end side in the first housing 1a. The light emitting element 2 emits ultraviolet light 8 toward the half mirror 3 by supplying electric power P from the outside. Examples of the light emitting element 2 include a light emitting diode element that emits ultraviolet light 8.

  The half mirror 3 is disposed at a substantially central position in the first housing 1 a with a predetermined inclination (for example, 45 degrees) with respect to the light emitting surface 2 a of the light emitting element 2, and is irradiated from the light emitting element 2. The ultraviolet light 8 is transmitted (or passed), and the light 9 containing the fluorescence 11 transmitted from the liquid film 12 side through the optical fiber 5 is separated into the ultraviolet light 8 and the fluorescence 11, and the separated fluorescence 11 is separated. The included light 9 is reflected to the ultraviolet light cut filter 6 side.

  The coupling 4 is disposed on the outer wall of the first casing 1a that is opposite to the light emitting element 2 side of the first casing 1a, and includes one end 5a of the optical fiber 5 and the first casing 1a. Are joined.

  The optical fiber 5 includes a core 5c that transmits light, a clad 5k that encloses the core 5c, and a covering member 5h that covers the clad 5k. The core 5c is formed of a translucent material such as glass fiber. The clad 5k is formed of a translucent material such as glass having a higher refractive index than the core 5c. The covering member 5h is formed of a material such as nylon. One end 5 a of the optical fiber 5 is disposed at a position where the ultraviolet light 8 from the light emitting element 2 that has passed through the half mirror 3 can be received, and the light emitting element of the first housing 1 a is further coupled by the coupling 4. It is joined to the outer wall of the 1st housing | casing 5a used as the opposite side to 2 side. On the other hand, the other end (tip) 5b side of the optical fiber 5 is inserted into the through hole 10h of the base material 10, and the tip 5b of the optical fiber 5 is connected to the surface 10a of the base material 10 to which the liquid film 12 adheres. It is located on the same plane and is arranged at a position where the ultraviolet light 8 received from the half mirror 3 side can be transmitted toward the liquid film 12. Here, in this example, only one optical fiber 5 is provided, and an optical path (core) for transmitting the ultraviolet light 8 from the light emitting element 2 that has passed through the half mirror 3 toward the liquid film 12; The optical path (core) for transmitting the light 9 including the fluorescence 11 emitted from the liquid film 12 toward the half mirror 3 is constituted by one optical path (core 5 c) of one optical fiber 5. However, in the present invention, the number of optical paths of the optical fiber 5, the configuration of the optical fiber, and the number of optical fibers are not limited.

  The ultraviolet light cut filter 6 is disposed substantially at the center of the second housing 1 b and can receive light 9 including the fluorescence 11 reflected from the liquid film 12 side reflected by the half mirror 3. Placed in position. The ultraviolet light cut filter 6 cuts (absorbs or blocks) the ultraviolet light 8 from the light 9 including the fluorescence 11 reflected by the half mirror 3 and transmits only the fluorescence 11 to the optical sensor 7 side.

  The optical sensor 7 receives the fluorescence 11 transmitted through the ultraviolet light cut filter 6 and detects the fluorescence intensity of the liquid film 12, and also detects a voltage value V (hereinafter, “ Output voltage value V ").

  Next, a method for measuring the thickness F of the liquid film 12 using the liquid film thickness measuring device 20 will be described.

  First, the power P is supplied to the light emitting element 2 at the timing when the thickness F of the liquid film 12 is measured, and the ultraviolet light 8 is emitted from the light emitting surface 2 a of the light emitting element 2. The ultraviolet light 8 emitted from the light emitting element 2 passes through the half mirror 3 and enters one end 5 a of the optical fiber 5, and further adheres onto the surface 10 a of the substrate 10 through the core 5 c of the optical fiber 5. Is transmitted. As a result, the portion A1 (hereinafter referred to as “fluorescent portion A1”) of the liquid film 12 facing the tip 5b of the optical fiber 5 is excited by the ultraviolet light 8 and emits light 9 including the fluorescence 11. The emitted light 9 including the fluorescence 11 is incident on the tip 5b of the optical fiber 5 and further transmitted to the one end 5a of the optical fiber 5 through the core 5c of the optical fiber 5, and further from the one end 5a of the optical fiber 5 to the half mirror. 3 is emitted. The light 9 including the fluorescence 11 reaching the half mirror 3 is separated into the ultraviolet light 8 and the fluorescence 11 by the half mirror 3, and the separated light 9 including the fluorescence 11 is cut into the ultraviolet light by the half mirror 3. The light 9 reflected toward the filter 6 and including the reflected fluorescence 11 reaches the ultraviolet light cut filter 6. Here, Fig.2 (a) shows the wavelength characteristic of the light 9 containing the fluorescence 11 before an ultraviolet-light cut. In FIG. 2A, the vertical axis indicates the intensity of the light 9 including the fluorescence 11, and the horizontal axis indicates the wavelength (nm). As shown in FIG. 2A, it can be seen that the light 9 including the fluorescence 11 has a wavelength characteristic having peaks in both the ultraviolet wavelength region and the fluorescence wavelength region.

  Next, only the fluorescence 11 is extracted from the light 9 including the fluorescence 11 that has reached the ultraviolet light cut filter 6 by the ultraviolet light cut filter 6. Here, FIG. 2B shows the transmittance characteristics of the ultraviolet light cut filter 6. In FIG. 2B, the vertical axis indicates the transmittance (%) of the ultraviolet light cut filter 6, and the horizontal axis indicates the wavelength (nm). As shown in FIG. 2B, the ultraviolet light cut filter 6 has a characteristic of absorbing light in a wavelength range of less than about 400 nm and transmitting light in a wavelength range of about 400 nm or more. Therefore, the ultraviolet light cut filter 6 cuts (absorbs) the ultraviolet light 8 from the light 9 including the fluorescence 11 reflected by the half mirror 3 and transmits only the fluorescence 11 to the optical sensor 7 side. Here, FIG. 2C shows the wavelength characteristic of the fluorescence 11 after the ultraviolet light is cut by the ultraviolet light cut filter 6. In FIG. 2C, the vertical axis represents the intensity of the fluorescence 11, and the horizontal axis represents the wavelength (nm).

  Next, the fluorescence 11 transmitted through the ultraviolet light cut filter 6 is received by the optical sensor 7. The optical sensor 7 detects the intensity of the fluorescence 11 of the fluorescence portion A1 of the liquid film 12 based on the amount of received light 11 of the fluorescence 11, and outputs a voltage value V corresponding to the detected intensity of the fluorescence 11 of the liquid film 12. . Here, FIG. 2D is an example of a graph showing the relationship between the output voltage value (V) from the optical sensor 7 and the thickness of the liquid film 12. As shown in FIG. 2D, the relationship between the output voltage value V from the optical sensor 7 and the thickness F of the liquid film 12 is proportional. Therefore, in the first embodiment, it is possible to calculate the thickness F of the fluorescent portion A1 of the liquid film 12 based on the output voltage value V from the optical sensor 7.

  Moreover, in this liquid film thickness measuring apparatus 20, the light emitting element 2, the half mirror 3, the ultraviolet light cut filter 6, and the optical sensor 7 are accommodated in one housing 1, and the liquid film thickness measuring apparatus. 20 has a compact system configuration. Therefore, in addition to preventing an increase in the cost of the liquid film thickness measuring device 20, mounting on an internal combustion engine (actual machine) or the like is facilitated.

  Further, in the liquid film thickness measuring device 20, the light path (core) for transmitting the ultraviolet light 8 from the light emitting element 2 that has passed through the half mirror 3 toward the liquid film 12 and the liquid film 12 are emitted. The optical path (core) for transmitting the light 9 including the fluorescence 11 toward the half mirror 3 is constituted by one optical path (core 5 c) of one optical fiber 5. Therefore, compared with the structure which transmits the light 9 containing the ultraviolet light 8 and the fluorescence 11 using a some optical fiber, the liquid film thickness measuring apparatus 20 can be made more compact, and the liquid film thickness is equivalent. The cost of the measuring device 20 can be reduced.

[Second Embodiment]
(Configuration of liquid film thickness measuring device)
Next, the configuration of the liquid film thickness measuring apparatus according to the second embodiment of the present invention will be described with reference to FIG. In the following, elements common to the first embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  FIG. 3A is a cross-sectional view schematically showing the configuration of the liquid film thickness measuring device 20z according to the second embodiment. FIG. 3B is a cross-sectional view of the main part in the vicinity of the optical path switching device 30, and of the two optical fibers 5x and 5y, the other end that is opposite to the one end 5ya of the optical fiber 5y using the optical fiber 5y. The operation | movement explanatory drawing of the optical path switching apparatus 30 when measuring the thickness F of the liquid film 12 (illustration abbreviation) which faces (tip; illustration abbreviation) is shown. FIG. 3C is a cross-sectional view of the main part in the vicinity of the optical path switching device 30, and of the two optical fibers 5x and 5y, the other end that is opposite to the one end 5xa of the optical fiber 5x using the optical fiber 5x. The operation | movement explanatory drawing of the optical path switching apparatus 30 when measuring the thickness F of the liquid film 12 (illustration abbreviation) which faces (tip; illustration abbreviation) is shown.

  The liquid film thickness measuring device 20 according to the first embodiment is configured to measure the thickness of one liquid film 12 using one optical fiber 5.

  In contrast, the liquid film thickness measuring device 20z according to the second embodiment has a configuration for measuring the thickness of the liquid film 12 at a plurality of locations using a plurality of optical fibers. Specifically, the liquid film thickness measuring device 20z according to the second embodiment includes an optical system main body 20x having the same configuration as that of the first embodiment, and an optical path switching device 30 joined to the optical system main body 20x. And two optical fibers (optical fiber 5x and optical fiber 5y) joined to the optical path switching device 30.

  The optical path switching device 30 includes a housing 21, a mirror 22, a motor 23, and a plurality of couplings 4.

  The housing 21 has, for example, a box shape, and is joined to the optical system main body 20 x via the coupling 4.

  The mirror 22 includes a reflection surface 22a that reflects received light. The mirror 22 is configured so that the ultraviolet light 8 from the light emitting element 2 side transmitted through the half mirror 3 is incident on the reflecting surface 22a of the mirror 22 at a predetermined inclination angle (for example, 45 degrees), and the liquid film 12 The light 9 including the fluorescence 11 emitted from the side through the optical fiber 5x or the optical path (core 5c) of the optical fiber 5y is incident on the reflecting surface 22a of the mirror 22 at a predetermined inclination angle (for example, 45 degrees). It is accommodated in the housing 21 in a state.

  The motor 23 is connected to the mirror 22 and rotates the mirror 22. An example of the motor 23 is a stepping motor.

  The optical fiber 5x has the same configuration as the optical fiber 5 described above. One end 5xa side of the optical fiber 5x is joined to the coupling 4 disposed on the outer wall of the housing 21. On the other hand, the other end side (tip side; not shown) opposite to the one end 5xa of the optical fiber 5x is inserted into a through hole 10h of the base material 10 (not shown), and the tip of the optical fiber 5x is Although not shown in the drawing, the ultraviolet light 8 that is located on the same surface as the surface 10a of the substrate 10 to which the liquid film 12 adheres and is incident from the one end 5xa side of the optical fiber 5x is input to the measurement portion of the liquid film 12. It is arranged at a position where transmission is possible.

  The optical fiber 5y has the same configuration as the optical fiber 5 described above. One end 5ya of the optical fiber 5y is joined to the coupling 4 disposed on the outer wall of the housing 21 and on the opposite side to the one end 5xa of the optical fiber 5x. On the other hand, the other end side (tip side; not shown) opposite to the one end 5ya of the optical fiber 5y is inserted into a through hole 10h of the base material 10 (not shown), and the tip of the optical fiber 5y is Although not shown, the ultraviolet light 8 that is located on the same surface as the surface 10a of the substrate 10 to which the liquid film 12 adheres and is incident from the one end 5ya side of the optical fiber 5y is applied to the liquid film 12 (the above-described light The fiber 5x is disposed at a position where transmission can be performed toward another measurement portion that is different from the measurement portion of the liquid film 12 that the tip of the fiber 5x faces.

  Next, a method for measuring the thickness F of the liquid film 12 using the liquid film thickness measuring device 20z will be described.

  In this optical path switching device 30, the motor 23 is configured such that the ultraviolet light 8 from the light emitting element 2 side that has passed through the half mirror 3 is reflected by the reflection surface 22 a of the mirror 22 and is out of two optical fibers (optical fiber 5 x and optical fiber 5 y). The light 9 including the fluorescence 11 emitted from one of the optical fibers through the optical fiber so as to be reflected toward the optical path (core 5 c) at one end of one of the optical fibers is reflected by the mirror 22. The rotation angle of the mirror 22 is controlled so as to be reflected toward the half mirror 3 by the surface 22a. For example, when the thickness F of the liquid film 12 is measured using the optical fiber 5y of the two optical fibers (the optical fiber 5x and the optical fiber 5y), the motor 23 is as shown in FIG. The rotation angle of the mirror 22 is controlled so that the reflection surface 22a of the mirror 22 faces the optical path (core 5c) of the one end 5ya of the optical fiber 5y. On the other hand, when measuring the thickness F of the liquid film 12 using the optical fiber 5x of the two optical fibers (the optical fiber 5x and the optical fiber 5y), the motor 23 is as shown in FIG. The rotation angle of the mirror 22 is controlled so that the reflection surface 22a of the mirror 22 faces the optical path (core 5c) of the one end 5xa of the optical fiber 5x.

  Thus, in this optical path switching device 30, by controlling the rotation angle of the mirror 22 through the motor 23, the optical path is switched to the optical path of the optical fiber to be measured among the optical fiber 5x and the optical fiber 5y. Thereby, the transmission of the ultraviolet light 8 emitted from the optical system main body 20x and the transmission of the light 9 containing the fluorescence 11 emitted from the liquid film 12 side are performed by the optical path of the optical fiber to be measured. As a result, it is possible to measure the thickness F of the liquid film 12 at a plurality of locations (in this example, the thicknesses of the measurement portion of the liquid film 12 and the thicknesses of the other measurement portions).

  In the liquid film thickness measuring apparatus 20z according to the second embodiment, the thickness F of the liquid film 12 is measured using two optical fibers (the optical fiber 5x and the optical fiber 5y). However, the liquid film thickness measuring apparatus according to the present invention is not limited to this, and the thickness F of the liquid film 12 may be measured using two or more optical fibers. For example, FIG. 4A is a cross-sectional view of a main part of an optical path switching device 31 according to another embodiment taken along the cutting line AA ′ in FIG. An example using the fiber 5 is shown. Similarly, FIG. 4B is a cross-sectional view of a main part of an optical path switching device 32 according to another embodiment corresponding to FIG. 4A, and an example in which six optical fibers 5 are used in the optical path switching device 32. Indicates. Similarly, FIG. 4C is a cross-sectional view of a main part of an optical path switching device 33 according to another embodiment corresponding to FIG. 4A, and an example in which eight optical fibers 5 are used in the optical path switching device 33. Indicates. 4A to 4C, the same elements as those in the optical path switching device 30 are denoted by the same reference numerals. Moreover, the operation principle of the optical path switching devices 31 to 33 is the same as that of the optical path switching device 30, and the description thereof is omitted.

[Application example for internal combustion engine]
When the liquid film thickness measuring device according to the present invention is applied to an internal combustion engine, a liquid film (for example, a fuel thin film having an additive that emits fluorescence when irradiated with ultraviolet light; The thickness F of the internal combustion engine can be appropriately controlled based on the measurement result. Therefore, an example in which the liquid film thickness measuring device 20z according to the second embodiment as an example of the liquid film thickness measuring device according to the present invention is applied to an internal combustion engine will be described below with reference to FIG.

(Configuration of control device for internal combustion engine)
FIG. 5 is a cross-sectional view schematically showing a configuration of a control device for an internal combustion engine to which the liquid film thickness measuring device 20z according to the second embodiment is applied. In FIG. 5, broken line arrows indicate gas flows, and solid line arrows indicate signal input and output.

  The control device 100 of the internal combustion engine (engine) 80 is a device that controls the internal combustion engine 80 by an ECU (Engine Control Unit) 112 as an example of an electronic vehicle operation control device, and mainly includes a cylinder 121 and a cylinder. A head 119, a fuel tank 115, a liquid film thickness measuring device 20z, and the like are provided. In addition to this, the control device 100 of the internal combustion engine 80 is provided with a key switch for starting and stopping the internal combustion engine 80 and electrical components, and for applying rotational force by cranking when the internal combustion engine 80 is started. Starter, a starter switch for detecting on / off operation of the starter, and the like are provided, but these are not shown in FIG.

  The cylinder 121 is disposed below the cylinder head 119. In the present embodiment, the number of cylinders 121 in the internal combustion engine 80 is not limited. A water jacket 122 through which cooling water for cooling each part of the internal combustion engine 80 is provided inside the cylinder 121 and the like. The temperature of the cooling water flowing through the water jacket 122 is detected by a water temperature sensor 110 attached to the cylinder 121. A piston 123 is disposed inside the cylinder 121 in a state where the piston 123 can reciprocate along the inner wall of the cylinder 121. The piston 123 is connected to the crankshaft 125 via a connecting rod 124. The reciprocating motion of the piston 123 is converted into a rotational motion by the connecting rod 124 and then transmitted to the crankshaft 125. Determination of the stroke position of the piston 123 in the cylinder 121, that is, cylinder determination is performed by detecting the rotational position (crank angle) of the crankshaft 125 by the crank angle sensor 111. Various controls including ignition timing control and fuel injection timing control in the internal combustion engine 80 are performed based on detection of the crank angle. A combustion chamber 106 is formed between the piston 123, the cylinder 121, and the cylinder head 119.

  The cylinder head 119 mainly includes an intake passage 128, a throttle valve 101, a surge tank 102, an intake system including an intake port 105 and an intake valve 107, an exhaust system including an exhaust valve 109 and an exhaust passage 120, an ignition device 118, and the like. Is provided. The air (intake) introduced from the outside passes through the intake passage 128, and the intake air is adjusted by the throttle valve 101, and the intake air is adjusted by the surge tank 102 and the intake port 105. To the combustion chamber (inside the cylinder) 106. The surge tank 102 is provided with an intake pressure sensor 103 for detecting the pressure of intake air in the surge tank 102. The intake valve 107 is controlled to be opened and closed by the ECU 112, thereby communicating / blocking the intake port 105 and the combustion chamber 106. Near the intake valve 107, a cam angle sensor 108 for detecting the angle of a cam (not shown) that drives the intake valve 107 is provided. The intake port 105 is provided with a fuel injection device (injector) 104. The combustion injection device 104 is connected to a fuel tank 115 that holds an appropriate amount of fuel (liquid film component) 127 via a fuel introduction path (fuel piping) 126. The combustion injection device 104 controls the fuel injection amount, fuel injection timing, and the like based on the signal Sig8 output from the ECU 50, and injects fuel (liquid film component) toward the intake port 105. The fuel injected toward the intake port 105 is further supplied into the combustion chamber 106.

  In the combustion chamber 106, the supplied air / fuel mixture is combusted by ignition by the ignition device 118. In this case, the piston 123 reciprocates along the inner wall of the cylinder 121 by the combustion, and this reciprocating motion is transmitted to the crankshaft 125 via the connecting rod 124 to rotate the crankshaft. Exhaust gas generated by the combustion of the air-fuel mixture in the combustion chamber 106 is discharged to the exhaust passage 120 and further discharged to the outside through a catalyst, a muffler and the like (not shown). The exhaust valve 109 is provided from the exhaust passage 120 side to the combustion chamber 106 side, and is controlled to be opened and closed by the ECU 112, thereby communicating / blocking the exhaust passage 120 and the combustion chamber 106.

  The liquid film thickness measuring device 20z starts measurement based on a signal Sig1 related to a measurement command supplied from the ECU 112 at a predetermined timing. In this example, the thickness of the liquid film of fuel attached to the wall surface 105a of the intake port 105 is measured. It plays the role of measuring F. Of the two optical fibers 5x and 5y in the liquid film thickness measuring device 20z, the tip 5xb of one optical fiber 5x is disposed on the same plane as the wall surface 105a of the intake port 105, and the wall surface 105a of the intake port 105 The other optical fiber 5y is used as an optical fiber for measuring the thickness F of the liquid film per unit fluorescence intensity, which will be described later.

  Although not shown, the ECU 112 includes arithmetic means including a CPU (Central Processing Unit) and storage means including a ROM (Read Only Memory) and a RAM (Random Access Memory). The ECU 112 sends a signal related to the thickness F of the liquid film from the optical sensor 7 of the liquid film thickness measuring device 20z (that is, a signal related to the output voltage value V corresponding to the fluorescence intensity of the fluorescent portion of the liquid film) Sig2, The crank angle signal 111 from the crank angle sensor 111 is related to the crank angle, the signal Sig4 is related to the coolant temperature from the water temperature sensor 110, the signal Sig5 is related to the cam angle from the cam angle sensor 108, and the intake pressure in the surge tank 102 from the intake pressure sensor 103. The signal Sig6 related to the signal, the signal IG related to the on / off operation of the key switch from the ignition terminal of the key switch, and the signal ST related to the on / off operation of the starter from the starter switch Based on this, the ECU 112 controls the internal combustion engine 80.

  In the present invention, the ECU 112, as will be described later, is a liquid film thickness conversion means for calculating the thickness of the liquid film per unit fluorescence intensity, and the liquid film adhesion amount for calculating the liquid film adhesion amount M from the liquid film thickness F. Calculation means, injection amount increase coefficient determination means for determining the injection amount increase coefficient Y during transient operation, in-cylinder inflow amount calculation means for calculating the inflow amount Ci into the combustion chamber (in-cylinder) 106, correction for the injection amount increase coefficient Y It functions as correction coefficient calculation means for calculating the coefficient x.

  Since the liquid film thickness measuring device 20z applied to the control device 100 of the internal combustion engine 80 has a compact configuration, it can be used as a feedback sensor that contributes to space saving of the internal combustion engine 80.

(Reference point calculation method for liquid film thickness)
Next, a method for calculating the reference point of the liquid film thickness F (the point at which the liquid film thickness F is 0, which will be used in the same meaning below) will be described with reference to FIG.

  FIG. 6A shows a time chart according to the reference point calculation method for the thickness F of the liquid film. In FIG. 6A, the vertical axis indicates the output state of the ON / OFF signal for operating the fuel injection device 104 and the output state of the ON / OFF signal for emitting (driving) the light emitting element 2. The horizontal axis indicates time. FIG. 6B shows the output voltage value V0 of the photosensor 7 corresponding to the reference point of the liquid film thickness F in FIG. 6A, and FIG. 6C shows 1 in FIG. The output voltage value V1 of the optical sensor 7 corresponding to the thickness F of the second liquid film is shown.

  Since the disturbance in the internal combustion engine 80 is large, it is difficult to take a reference point for the thickness F of the liquid film. In the present embodiment, when the internal combustion engine 80 is cranked (when the internal combustion engine 80 is started by the starter) before fuel injection is set to the reference state, the wall surface of the internal combustion engine 80 from the light emitting element 2 side in the reference state. For example, the liquid film adhering to the wall surface 105a of the intake port 105 is irradiated with the ultraviolet light 8 through the optical fiber 5x, and the intensity of the fluorescence 11 emitted from the liquid film by the irradiation is detected by the optical sensor 7 and detected. The output voltage value V0 from the optical sensor 7 corresponding to the intensity of the fluorescence 11 is set as a reference point for the thickness F of the liquid film.

  More specifically, first, when the signal IG related to the ON operation of the key switch from the ignition terminal of the key switch and the signal ST related to the ON operation of the starter from the starter switch are respectively input to the ECU 112, the ECU 112 At the time of 80 cranking, before the fuel injection to the intake port 105 is performed by the fuel injection device 104 (the output of the fuel injection signal Sig8 is turned ON), the liquid film thickness measuring device 20z A signal (reference point correction signal for driving the light emitting element 2) Sig1 for measuring the film thickness F is output.

  Thereby, the ultraviolet light 8 is emitted from the light emitting element 2, and the emitted ultraviolet light 8 is irradiated toward the liquid film adhering to the wall surface 105a of the intake port 105 from the tip 5xb of the optical fiber 5x based on the principle described above. Is done. Here, various additives are usually mixed in the liquid film, and when the additive contained in the liquid film is irradiated with ultraviolet light 8, the fluorescent part of the additive is excited and contains fluorescence 11. Light 9 is emitted. When the light 9 containing the fluorescence 11 is received by the tip 5xb of the optical fiber 5x, only the fluorescence 11 is extracted from the received light 9 containing the fluorescence 11 by the ultraviolet light cut filter 6 based on the principle described above. The fluorescent light 11 is received by the optical sensor 7. The optical sensor 7 detects the intensity of the fluorescent portion of the received liquid film and outputs a signal Sig2 related to the output voltage value V0 corresponding to the detected intensity of the fluorescence 11 of the liquid film to the ECU 112. When the ECU 112 receives the output voltage value V0, the ECU 112 sets the output voltage value V0 as a reference point at which the liquid film thickness F becomes zero. Based on this reference point, the thickness F of the liquid film is converted from the output voltage value V from the optical sensor 7.

  It should be noted that deposits and the like are easily deposited on the wall surface of the internal combustion engine 80, and therefore deposits and the like are likely to adhere to the tip 5xb of the optical fiber 5x and the tip 5yb of the optical fiber 5y. If deposits or the like adhere to the tip 5xb of the optical fiber 5x and the tip 5yb of the optical fiber 5y, the measurement sensitivity of the liquid film thickness F by the liquid film thickness measuring device 20z may be reduced. .

  Therefore, in the present invention, it is preferable to apply a photocatalyst or the like that decomposes deposits or the like to each of the tip 5xb of the optical fiber 5x and the tip 5yb of the optical fiber 5y. Thereby, adhesion of deposits etc. to the tip 5xb of the optical fiber 5x and the tip 5yb of the optical fiber 5y can be suppressed, and the measurement sensitivity of the liquid film thickness F by the liquid film thickness measuring device 20z is suppressed from being lowered. it can.

(Conversion method from optical sensor output voltage value to liquid film thickness)
Next, a method for converting the output voltage value V of the optical sensor 7 to the liquid film thickness F will be described.

  In the present embodiment, the liquid film thickness measuring device 20z is based on the reference voltage value V0 calculated by the above-described liquid film thickness reference point calculation method based on the signal Sig1 related to the measurement command from the ECU 112, and every cycle. The output voltage value Vi (i is a natural number; for example, “V1” is the output voltage value related to the first cycle shown in FIG. 6C, and “V2” is the second cycle calculated in Based on the output voltage value,..., “Vi” indicates the output voltage value in the i-th cycle, respectively, and the liquid film thickness F is calculated for each cycle. Note that “one cycle” means, for example, when the internal combustion engine has four cylinders, a series of strokes including an intake stroke, a compression stroke, a combustion / expansion stroke, and an exhaust stroke.

  More specifically, the ECU 112 is after the reference voltage value V0 is measured by the liquid film thickness measuring device 20z and during the period in which the intake valve 107 and the exhaust valve 109 are closed after the end of the intake stroke. Based on the following formula 1, the thickness F of the liquid film for each cycle adhering to the wall surface 105a of the intake port 105 of the internal combustion engine 80 is calculated.

Fi = Vi−V0 (Subscript “i” indicates the number of cycles) (Formula 1)
Here, the liquid film of the internal combustion engine 80 is usually mixed with a fluorescent substance (for example, contained in an additive of gasoline or diesel), but even if the same fuel (liquid film) is used for each production lot. However, the content of the fluorescent substance is different. For this reason, the intensity of the fluorescence 11 of the liquid film differs for each fuel production lot, and therefore, the thickness F of the liquid film also differs for each fuel production lot. In order to remove such harmful effects, it is necessary to calibrate the fluorescence intensity of the liquid film continuously.

  Therefore, in the present embodiment, the fuel introduction path 126 is provided with a specified thickness portion, the fuel flowing into the specified thickness portion is fluorescent, and the thickness of the liquid film per unit fluorescence intensity is based on the intensity of the fluorescence. By calculating the thickness and reflecting the calculated value in the above equation 1, the fluorescence intensity of the liquid film is constantly calibrated.

  Hereinafter, this point will be described with reference to FIGS. 5 and 7A.

  FIG. 7A is an enlarged cross-sectional view corresponding to the vicinity of the region A10 of the fuel introduction path 126 in FIG. 5, and schematically shows a specified thickness portion related to the throttle method provided in the middle of the fuel introduction path 126. . In addition, the arrow direction in Fig.7 (a) has shown the direction through which a fuel flows.

  As shown in FIG. 7A, in the middle of the fuel introduction path 126, the fuel tank 115 and the fuel injection device 104 are narrowed down from the main pipe 126a that connects the fuel tank 115 and the specified thickness. A defined thickness portion (rectangular one-dot chain line portion) 116 having a length L (length or diameter in a direction perpendicular to the direction of fuel flow) L is provided. Further, the tip 5yb of the optical fiber 5y is disposed at a position where the prescribed thickness portion 116 is irradiated with ultraviolet light.

  Under the above configuration, the liquid film thickness measuring device 20z converts the ultraviolet light 8 emitted from the light emitting element 2 into the tip 5yb of the optical fiber 5y based on the principle described above based on the signal Sig1 related to the measurement command from the ECU 112. To the fuel flowing through the defined thickness portion 116. Thereby, the light 9 containing the fluorescence 11 is emitted from the fluorescent portion A11 of the additive contained in the fuel. When the light 9 including the fluorescence 11 is received by the tip 5yb of the optical fiber 5y, only the fluorescence 11 is extracted from the received light 9 including the fluorescence 11 by the ultraviolet light cut filter 6 based on the principle described above. The fluorescent light 11 is received by the optical sensor 7. The optical sensor 7 detects the intensity of the fluorescent portion A11 of the received fuel and outputs a signal Sig2 related to the output voltage value Vbase corresponding to the detected fluorescence intensity of the fuel to the ECU 112.

  The ECU 112 functions as a liquid film thickness conversion means for calculating the thickness of the liquid film per unit fluorescence intensity, and the specified thickness L in the specified thickness portion 116 and the specified thickness portion detected by the optical sensor 7. The thickness k of the liquid film per unit fluorescence intensity is calculated based on the output voltage value Vbase corresponding to the intensity of the fluorescence 11 at 116. For example, the ECU 112 calculates the liquid film thickness k per unit fluorescence intensity based on the following Equation 2.

k = L / Vbase (Formula 2)
Here, in the right term of Equation 2 above, “L” is the thickness (diameter) of the specified thickness portion 116, and “Vbase” is the output corresponding to the intensity of the fluorescence 11 of the specified thickness portion 116. It is a voltage value.

  Next, the ECU 112 sets the liquid film (liquid film) thickness k per unit fluorescence intensity, the reference voltage value V0 described above, and the output voltage value Vi from the optical sensor 7 calculated for each cycle. Based on this, the liquid film thickness Fi for each cycle is calculated.

  For example, the ECU 112 calculates the liquid film thickness Fi based on the following Equation 3.

Fi = k × (Vi−V0) (Subscript “i” indicates the number of cycles) (Formula 3)
Thus, the thickness F of the liquid film adhering to the wall surface of the internal combustion engine 80, for example, the wall surface 105a of the intake port 105, is the difference between the output voltage value Vi with respect to the reference voltage value V0 and the thickness k per unit fluorescence intensity. Is calculated by

  In the present invention, in order to calculate the thickness F of the liquid film more accurately, it is desirable to remove measurement noise caused by the liquid film thickness measuring device 20z and the like. In this case, the thickness F of the liquid film is averaged at every predetermined crank interval (for example, the thickness F of the liquid film is measured a plurality of times for each predetermined crank angle, and the averaged value is used as the cycle. Measurement noise caused by the liquid film thickness measuring device 20z or the like can be removed by causing the ECU 112 to perform the process of setting the measured value in (1).

  In the present invention, the configuration of the specified thickness portion 116 is not limited to the above-described diaphragm method, and various methods can be employed. For example, FIG. 7B is an enlarged cross-sectional view corresponding to the vicinity of the region A10 of the fuel introduction path 126 in FIG. 5 and schematically shows a specified thickness portion of the bypass system provided in the middle of the fuel introduction path 126. Show. In the following, elements common to those in FIG. 7A are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  In this example, a main pipe 126 a that connects the fuel tank 115 and the fuel injection device 104 and a bypass pipe 126 b that connects the upstream of the main pipe 126 a and the downstream 126 a thereof are provided in the middle of the fuel introduction path 126. The bypass pipe 126b is provided with a specified thickness portion 116 (rectangular one-dot chain line portion) having a specified thickness L (length or diameter in a direction perpendicular to the fuel flow direction) L. In the present invention, the thickness k of the liquid film per unit fluorescence intensity may be calculated based on the above formula 2 using the specified thickness portion 116 according to the bypass method.

(Conversion method from liquid film thickness to liquid film adhesion)
Next, a conversion method from the thickness of the liquid film to the adhesion amount of the liquid film will be described with reference to FIG.

  FIG. 8A shows a liquid film thickness-liquid film adhesion amount conversion map for converting the liquid film thickness F attached to the wall surface of the internal combustion engine 80, for example, the wall surface 105a of the intake port 105, to the liquid film adhesion amount M. Indicates. In FIG. 8A, the horizontal axis indicates the thickness of the liquid film adhering to the wall surface 105a of the intake port 105, and the vertical axis indicates the amount of liquid film adhering to the wall surface 105a of the intake port 105. A graph gx in FIG. 8A is a graph having a gradient (inclination) α indicating the relationship between the thickness F of the liquid film and the amount of adhesion of the liquid film.

  The ECU 112 functions as a liquid film adhesion amount calculating means for calculating the adhesion amount M of the liquid film adhering to the wall surface 105a of the intake port 105 of the internal combustion engine 80 (not shown). The ECU 112 calculates the thickness F of the liquid film adhering to the wall surface 105a of the intake port 105 of the internal combustion engine 80 calculated above, and the liquid film thickness-liquid shown in FIG. 8A stored in the storage means of the ECU 112. Based on the film adhesion amount conversion map, the liquid film adhesion amount M on the wall surface 105a of the intake port 105 is calculated. For example, the liquid film adhesion amount calculation means calculates the liquid film adhesion amount M based on the following Equation 4.

Mi = α × {k × (Vi−V0)} (“i” indicates the number of cycles) (Formula 4)
Here, in the above Equation 4, “α” indicates the gradient (inclination) of the graph shown in the liquid film thickness-liquid film adhesion amount conversion map of FIG.

  In the present invention, by disposing the tips of the plurality of optical fibers 5 with respect to a plurality of locations on the wall surface of the internal combustion engine 80, for example, the wall surface 105a of the intake port 105, a liquid film corresponding to each of the plurality of locations is provided. The thickness F can be calculated. However, in this case, the thickness F of the liquid film adhering to each of the plurality of locations on the wall surface 105a of the intake port 105 usually differs depending on the shape of each of the plurality of locations on the wall surface 105a of the intake port 105, and so on. Unless the liquid film thickness-liquid film adhesion amount conversion map corresponding to each of the plurality of locations on the wall surface 105a of 105 is used, the adhesion amount M of the liquid film at each of the plurality of locations on the wall surface 105a of the intake port 105 is calculated. I can't.

  Therefore, under such a configuration, the liquid film for converting the thickness F of the liquid film at a plurality of locations (a plurality of measurement points) on the wall surface of the internal combustion engine 80 into the amount M of adhesion of the liquid film at the measurement points. A thickness-liquid film adhesion amount conversion map is stored in the storage means of the ECU 112. For example, FIG. 8B shows a liquid for calculating a liquid film adhesion amount M corresponding to each of the thicknesses F of the liquid film at each location (measurement points 1 to 4) of the wall surface of the internal combustion engine 80. The film thickness-liquid film adhesion amount conversion map is shown. In FIG. 8B, “α” indicates the gradient (slope) of the graph related to measurement point 1, “β” indicates the gradient (slope) of the graph related to measurement point 2, and “γ” indicates measurement point 3. Represents the slope (slope) of the graph according to, and “ζ” represents the slope (slope) of the graph according to measurement point 4. By using this liquid film thickness-liquid film adhesion amount conversion map, the liquid film adhesion corresponding to each of the thicknesses F of the liquid film at each location (measurement points 1 to 4) of the wall surface of the internal combustion engine 80 is obtained. The amount M can be calculated. Further, since the liquid film adhesion amount M can be calculated, the fuel injection control by the fuel injection device 104 of the internal combustion engine 80 can be performed with high accuracy based on this.

(Fuel injection control processing during transient operation)
Appropriate fuel injection control through the fuel injection device 104 is performed during transient operation in which the operating state of the internal combustion engine 80 fluctuates, such as during acceleration or deceleration of the vehicle (particularly during transient operation when the internal combustion engine 80 is cold). Otherwise, there is a problem that particulate matter (smoke), nitrogen oxides (NOx), hydrocarbons (HC), and the like are exhausted in a large amount into the atmosphere, resulting in emission deterioration.

  Therefore, in the present embodiment, during the transient operation of the internal combustion engine 80, the liquid film thickness measuring device 20z is used to measure the thickness F of the liquid film adhering to the wall surface of the internal combustion engine 80. Based on the above, the amount M of the liquid film is calculated from the thickness F of the liquid film, and based on this, the fuel injection through the fuel injection device 104 is appropriately controlled, and at the same time the emission is reduced.

  Hereinafter, the fuel injection control process during the transient operation according to the embodiment of the present invention will be described with reference to FIG. 9 and the like.

  FIG. 9 shows a flowchart relating to fuel injection control processing during transient operation of the internal combustion engine. The fuel injection control process during the transient operation is executed simultaneously with the start of the transient operation of the internal combustion engine 80, and is repeatedly executed for each cycle until the transient operation ends. Note that “i” as a subscript of each variable in each process of FIG. 9 represents the number of 1, 2,..., I cycles.

  The ECU 112 functions as an injection amount increase coefficient determining means, and first determines an injection amount increase coefficient Y during transient operation (step S1). Here, the injection amount increase coefficient Y is calculated based on the following Equation 5.

Y = y × x (Formula 5)
Here, in the above equation 5, “y” is a reference injection amount increase coefficient determined based on the operating state of the internal combustion engine 80, and “x” is a correction coefficient for the reference injection amount increase coefficient y. Note that x = 1 (initial value) is set in the first cycle during transient operation.

  Next, the ECU 112 calculates the fuel injection period based on the injection amount increase coefficient Y calculated in step S1 (step S2), and the fuel injection device 104 is calculated based on the signal Sig8 output from the ECU 112. Fuel of a predetermined injection amount (fuel injection amount = Qi) is injected toward the intake port 105 only during the fuel injection period.

  Next, after the end of the intake stroke, the ECU 112 outputs a signal Sig1 related to the measurement command to the liquid film thickness measuring device 20z, and an output voltage output from the optical sensor 7 of the liquid film thickness measuring device 20z. Get the value Vi. The ECU 112 calculates the thickness Fi {= k × (Vi−V0)} of the liquid film adhering to the wall surface 105a of the intake port 105 based on the above equation 3 (step S5).

  Next, the ECU 112 functions as a liquid film adhesion amount calculation means, and calculates the liquid film thickness Fi adhering to the wall surface 105a of the intake port 105 based on the above-described equation 4 as the liquid film adhesion amount Mi [= α ×. {K × (Vi−V0)}] (step S6).

  Next, the ECU 112 calculates a difference ΔM between the liquid film adhesion amount Mi corresponding to the current cycle and the liquid film adhesion amount Mi-1 corresponding to the previous cycle (step S7).

  Next, the ECU 112 determines whether or not ΔM calculated in step S7 is substantially 0 (ΔM≈0) (step S8). In this step S8, when ΔM is substantially 0, the ECU 112 determines that the amount Mi of the liquid film adhering to the wall surface 105a of the intake port 105 has become substantially constant, and the fuel injection during the transient operation is performed. The execution of the control process is terminated (step S8; Yes). On the other hand, when ΔM is not substantially 0 (step S8; No), the ECU 112 functions as the in-cylinder inflow amount calculating means, and the fuel injection amount Qi in the current cycle (i cycle) and the current cycle (i cycle). ) To calculate the current inflow amount Ci of the fuel into the combustion chamber (in-cylinder) 106 (step S9). Here, when “Mi” is the amount of liquid film adhering to the wall surface 105 a of the intake port 105, the in-cylinder fuel inflow amount Ci is calculated based on the following Equation 6.

Ci = Qi−Mi (Formula 6)
Next, the ECU 112 functions as a correction coefficient calculation means, and the in-cylinder fuel inflow amount Ci calculated in step S9 and the reference value (in-cylinder inflow amount reference value determined based on the number of cycles elapsed from the start of transient operation). Based on Cbase, the correction coefficient x for determining the injection amount increase coefficient Y is calculated so that the current in-cylinder fuel inflow amount Ci becomes the reference value (reference inflow amount) Cbase. (Step S10). Specifically, the correction coefficient calculation means calculates based on the following equation 7 with reference to the elapsed cycle number-in-cylinder fuel inflow amount map from the start of transient operation shown in FIG.

x = Cbase / Ci (Formula 7)
In FIG. 10, the vertical axis indicates the in-cylinder fuel inflow amount C, the horizontal axis indicates the number of elapsed cycles since the start of transient operation, and the graph indicates the cylinder determined based on the number of elapsed cycles since the start of transient operation. The reference value Cbase of the inflow amount is shown respectively.

  Here, in the i-th cycle, when the in-cylinder fuel inflow amount Ci is smaller than the reference value (triangle mark) Cbase (circle mark), the value of the correction coefficient x becomes large. The value of the injection amount increase coefficient Y is also increased. On the other hand, in the i-th cycle, when the in-cylinder fuel inflow amount Ci is larger than the reference value (triangle mark) Cbase (square mark), the value of the correction coefficient x becomes small. The value of the quantity increase coefficient Y is also reduced.

  The fuel injection control process during the transient operation described above is performed until a predetermined condition (ΔM is substantially 0) is satisfied. As a result, during the transient operation of the internal combustion engine 80 (particularly during the transient operation when the internal combustion engine 80 is cold), highly accurate fuel injection through the fuel injection device 104 is performed, so that particulate matter (smoke), nitrogen It is possible to suppress a large amount of oxide (NOx), hydrocarbon (HC), and the like from being discharged into the atmosphere, and it is possible to reduce emissions.

[Modification]
In the internal combustion engine 80, the liquid film thickness measuring device 20z according to the second embodiment is applied. However, the present invention is not limited thereto, and in the present invention, the liquid film thickness measuring device 100 according to the first embodiment is used. May be applied.

It is sectional drawing which shows the structure of the liquid film thickness measuring apparatus which concerns on 1st Embodiment of this invention. The graph which shows the relationship between the wavelength characteristic of the light containing fluorescence which concerns on the liquid film thickness measuring apparatus of 1st Embodiment, the wavelength characteristic of fluorescence, the transmittance | permeability characteristic of an ultraviolet-light cut filter, and the output voltage of an optical sensor, and a liquid film thickness It is. It is sectional drawing which shows the structure of the liquid film thickness measuring apparatus provided with the optical path switching apparatus which concerns on 2nd Embodiment of this invention. It is principal part sectional drawing which shows the structure of the optical path switching apparatus which concerns on the various examples of this invention. It is sectional drawing which shows the whole structure of the internal combustion engine to which the liquid film thickness measuring apparatus of this invention is applied. The time chart which concerns on the zero point correction method of the fluorescence intensity at the time of the liquid film thickness measurement using a liquid film thickness measuring apparatus is shown. It is principal part sectional drawing of the internal combustion engine corresponding to area | region A10 of FIG. 5, and is explanatory drawing about an example of the conversion method from the output voltage value of an optical sensor to a liquid film thickness. The liquid film thickness-liquid film adhesion amount conversion map for converting from the thickness of a liquid film to the adhesion amount of a liquid film is shown. The flowchart which concerns on the fuel-injection control process at the time of the transient operation which concerns on this embodiment is shown. 6 shows an in-cylinder inflow map of the number of cycles elapsed from the start of transient operation used when calculating a correction coefficient x for determining an injection amount increase coefficient Y.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Case 2 Light emitting element 3 Half mirror 4 Coupling 5, 5x, 5y Optical fiber 6 Ultraviolet light cut filter 7 Optical sensor 8 Ultraviolet light 9 Light containing fluorescence 10 Base material 11 Fluorescence 12 Liquid film 20, 20z Liquid film thickness Measuring device 20x Optical system body 22 Mirror 22a Reflecting surface 23 Motor 30, 31, 32, 33 Optical path switching device 80 Internal combustion engine 100 Control device for internal combustion engine 104 Fuel injection device 105 Intake port 105a Wall surface 107 Intake valve 109 Exhaust valve 112 ECU
115 Fuel tank 116 Specified thickness portion 126 Fuel introduction path

Claims (11)

A liquid film thickness measuring device that measures the thickness of the liquid film based on the intensity of fluorescence emitted from the liquid film by irradiation of ultraviolet light to the liquid film,
A light emitting element for emitting the ultraviolet light;
A half mirror that transmits the ultraviolet light from the light emitting element and reflects the light containing the fluorescence from the liquid film;
An optical fiber that transmits the ultraviolet light transmitted through the half mirror toward the liquid film, and transmits light including the fluorescence emitted from the liquid film toward the half mirror;
An ultraviolet light cut filter that cuts ultraviolet light from the light containing the fluorescence reflected by the half mirror and transmits only the fluorescence; and
An optical sensor that receives the fluorescence transmitted through the ultraviolet light cut filter and detects the fluorescence intensity of the liquid film, and outputs a voltage value corresponding to the detected fluorescence intensity. Liquid film thickness measuring device. The optical fiber is one,
The optical fiber transmits the ultraviolet light from the light emitting element that has passed through the half mirror toward the liquid film through a single optical path, and transmits the light containing the fluorescence emitted from the liquid film. The liquid film thickness measuring apparatus according to claim 1, wherein the liquid film thickness is transmitted toward the half mirror.   3. The liquid film thickness measuring device according to claim 1, wherein the light emitting element, the half mirror, the ultraviolet light cut filter, and the optical sensor are accommodated in one casing. 4. One end of the optical fiber is disposed at a position capable of receiving the ultraviolet light transmitted through the half mirror,
4. The other end of the optical fiber is disposed at a position where the received ultraviolet light can be transmitted toward the liquid film. 5. Liquid film thickness measuring device. An optical path switching device further comprising: a mirror including a reflecting surface for reflecting the received light; and a motor for controlling a rotation angle of the mirror;
Around the mirror, one end of the plurality of optical fibers is arranged at an appropriate interval, and the other end of the plurality of optical fibers is arranged at the plurality of measurement portions of the liquid film, respectively. And
The motor is configured such that the ultraviolet light from the light emitting element side that has passed through the half mirror is directed toward the optical path on the one end side of the optical fiber among the plurality of optical fibers by the reflecting surface of the mirror. The light including the fluorescence emitted from the liquid film side through the optical path of the one end of the optical fiber is reflected to the half mirror side by the reflecting surface of the mirror. The liquid film thickness measuring apparatus according to claim 1, wherein the rotation angle of the mirror is controlled as described above. The liquid film thickness measuring device according to any one of claims 1 to 5,
The control apparatus for an internal combustion engine, wherein the liquid film thickness measuring device calculates a thickness of the liquid film adhering to a wall surface of the internal combustion engine.   The liquid film thickness measuring device uses a voltage value from the optical sensor obtained in a reference state before fuel injection during cranking of the internal combustion engine as a reference voltage value at which the liquid film thickness becomes zero. The control apparatus for an internal combustion engine according to claim 6, wherein: A fuel introduction path through which fuel as a component of the liquid film is introduced, and a liquid film thickness conversion means for calculating the thickness of the liquid film per unit fluorescence intensity,
The fuel introduction path has a defined thickness portion having a defined thickness;
The intensity of the fluorescence emitted from the fuel of the specified thickness portion by the irradiation of the ultraviolet light is detected by the optical sensor through the optical fiber provided in the specified thickness portion,
The liquid film thickness conversion means is based on the prescribed thickness in the prescribed thickness portion and the intensity of the fluorescence in the prescribed thickness portion detected by the photosensor. 8. The control device for an internal combustion engine according to claim 6, wherein the thickness of the liquid film is calculated. A cylinder, and an intake valve and an exhaust valve provided corresponding to the cylinder,
The liquid film thickness measuring device is configured to provide a wall surface of the internal combustion engine in a cycle from the intake stroke to the exhaust stroke during a period in which the intake valve and the exhaust valve are closed after completion of the intake stroke in the cylinder. The control device for an internal combustion engine according to any one of claims 6 to 8, wherein a thickness of the liquid film adhering to the gas is measured. In order to calculate the liquid film thickness-liquid film adhesion amount conversion map for converting the liquid film thickness into the liquid film adhesion amount, and the liquid film adhesion amount adhering to the wall surface of the internal combustion engine. A liquid film adhesion amount calculating means,
The liquid film adhesion amount calculating means calculates the adhesion amount of the liquid film based on the thickness of the liquid film adhering to the wall surface of the internal combustion engine and the liquid film thickness-liquid film adhesion amount conversion map. The control device for an internal combustion engine according to any one of claims 6 to 9, wherein: An injection amount increase coefficient determining means for determining an injection amount increase coefficient of the fuel for the cylinder based on a reference injection amount increase coefficient and a correction coefficient of the fuel for the cylinder;
In-cylinder inflow amount calculation means for calculating the inflow amount of the fuel per one fuel injection into the cylinder;
Correction coefficient calculating means for calculating the correction coefficient,
During the transition of the internal combustion engine,
The in-cylinder inflow amount calculation unit per injection is calculated by the liquid film adhesion amount calculation unit corresponding to the current cycle calculated by the liquid film adhesion amount calculation unit and the previous time calculated by the liquid film adhesion amount calculation unit. Based on the difference between the amount of the liquid film adhering to the cycle and calculating the inflow amount of the fuel per one fuel injection,
The correction coefficient calculating means calculates the correction coefficient so that the calculated fuel inflow amount per one fuel injection becomes a reference inflow amount of the fuel into the cylinder,
11. The injection amount increase coefficient determining means determines an injection amount increase coefficient of the fuel in the next cycle based on the calculated correction coefficient and the reference injection amount increase coefficient. The control apparatus of the internal combustion engine described in 1.

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