JP6139156B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine. More particularly, the present invention relates to a control device for an internal combustion engine that can improve startability while suppressing deterioration of emission and fuel consumption in an internal combustion engine that operates with a mixed fuel.

Due to the recent increase in awareness of global environmental protection, plant-derived alcohols called "biomass ethanol" and "bioethanol" are mixed with conventional gasoline, for example, as fuel for internal combustion engines mounted on vehicles, etc. Use is becoming popular. As a raw material for biomass ethanol, plant resources containing a large amount of sugar or starch are suitable. At present, for example, molasses derived from sugarcane (mainly South America), corn (mainly US), and sugar beet ( Mainly Europe) is the main raw material for biomass ethanol. Development of biomass ethanol using plants other than these as raw materials is also underway. Since these plants absorb carbon dioxide (CO ₂ ) in the atmosphere, even if CO ₂ is generated by burning fuel made from these plants, the absolute amount of CO ₂ as a whole is reduced. Biomass ethanol is positioned as a fuel that is friendly to the global environment, based on the concept of “carbon neutral” that does not increase.

  Examples of a vehicle that can use an alcohol-mixed fuel obtained by mixing ethanol and conventional gasoline as described above as a fuel for an internal combustion engine include a flex-fuel vehicle (FFV) such as an ethanol flex-fuel vehicle. It is done. For example, ethanol FFV can use an alcohol-mixed fuel comprising ethanol and gasoline mixed at various ratios as a fuel for an internal combustion engine.

  By the way, ethanol has poor evaporation characteristics at a low temperature (having a high boiling point) as compared with gasoline, so that the startability and drivability of the internal combustion engine are deteriorated under a low engine temperature condition (for example, during cold start). Tend. Therefore, in this technical field, the injection timing of the mixed fuel is adjusted in accordance with the ethanol content in the mixed fuel, and the fuel is injected into the combustion chamber at a high temperature and high pressure near the top dead center of the compression stroke (in-cylinder It has been proposed to promote the vaporization of the mixed fuel by direct injection) and improve the startability and drivability of the internal combustion engine (see, for example, Patent Document 1).

  On the other hand, in an internal combustion engine equipped with an electronically controlled fuel injection device, correction for increasing the fuel injection amount during cranking is generally performed for the purpose of improving the startability. In particular, at the time of cold start, taking into account the fact that the fuel is not sufficiently vaporized and that the viscosity of the lubricating oil is high and the friction loss is large, the fuel injection amount is generally increased significantly. The same correction is generally performed in an internal combustion engine that operates with a mixed fuel. In addition, as described above, ethanol has poor evaporation characteristics at low temperatures (boiling point is high) compared to gasoline, so that the higher the ethanol content in the mixed fuel, the more greatly the fuel injection amount is increased. To be controlled.

  The above-described control is performed by, for example, mixing data stored in a data storage unit provided in a control device that controls fuel injection (for example, an electronic control unit (ECU) for controlling an internal combustion engine). It can be executed by setting a fuel injection amount corresponding to the ethanol content in the mixed fuel based on a data table (for example, a map) that defines the correspondence between the ethanol content in the fuel and the fuel injection amount. it can.

  As described above, according to the control that performs a large increase in the fuel injection amount in accordance with the ethanol content in the mixed fuel, the startability and drivability of the internal combustion engine can be improved. However, in such control, for the purpose of surely avoiding problems such as engine stall, it is generally set so that the fuel injection amount is slightly excessive in anticipation of low ethanol evaporation characteristics. It is. As a result, for example, there is a possibility of causing problems such as emission and deterioration of fuel consumption. Therefore, in order to improve startability while suppressing deterioration of emissions and fuel consumption in an internal combustion engine that operates with a mixed fuel, the amount of vaporized mixed fuel (vaporization amount) that actually contributes to the operation of the internal combustion engine is accurately determined. It is important to grasp and control so that the minimum amount of fuel required to start the internal combustion engine is supplied to the combustion chamber.

  However, as described above, in the internal combustion engine according to the related art that operates with the mixed fuel, the fuel is based on the ethanol content in the mixed fuel (for example, the mixed fuel stored in the fuel tank) before vaporization. The injection amount is controlled. However, as described above, since the evaporation characteristics are different between ethanol and gasoline, the ethanol content in the mixed fuel before vaporization does not necessarily match the ethanol content in the mixed fuel after vaporization. Thus, not only ethanol, but a mixture obtained by mixing fuel with relatively poor evaporation characteristics (relatively high boiling point) and fuel with relatively good evaporation characteristics (relatively low boiling point) In an internal combustion engine according to the prior art that operates with fuel, it is possible to accurately grasp the amount of vaporized mixed fuel (vaporization amount) that actually contributes to the operation of the internal combustion engine, while suppressing the deterioration of emissions and fuel consumption. It is still difficult to improve.

  As described above, in the technical field, there is a continuous demand for a technology that can improve startability while suppressing deterioration of emission and fuel consumption in an internal combustion engine that operates with a mixed fuel.

JP 2009-221963 A

  As described above, in the technical field, there is a continuous demand for a technology that can improve startability while suppressing deterioration of emission and fuel consumption in an internal combustion engine that operates with a mixed fuel. That is, an object of the present invention is to provide a control device for an internal combustion engine that can improve startability while suppressing deterioration of emission and fuel consumption in an internal combustion engine that operates with a mixed fuel.

The above object of the present invention is to
An injection means that operates by a mixed fuel including a first fuel component and a second fuel component having a boiling point higher than that of the first fuel component, and that directly injects the mixed fuel into a combustion chamber; An internal combustion engine control device for controlling an internal combustion engine comprising ignition means for igniting the mixed fuel in a combustion chamber,
A vaporization amount detecting means for detecting or estimating the vaporization amount of the first fuel component and the vaporization amount of the second fuel component in the combustion chamber;
A surplus vaporization amount obtained by subtracting the required vaporization amount required for ignition of the mixed fuel in the combustion chamber from the vaporization amount of the mixed fuel detected or estimated by the vaporization amount detection means is predetermined. If it is less than the first threshold, control either or both of the injection means and the ignition means to increase the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber,
When the excess vaporization amount is equal to or greater than a predetermined second threshold value that is greater than the first threshold value, the mixed fuel in the combustion chamber is controlled by controlling either or both of the injection means and the ignition means. Reduce the amount of vaporization at the time of ignition,
This is achieved by a control device for an internal combustion engine.

  ADVANTAGE OF THE INVENTION According to this invention, in the internal combustion engine which operate | moves with a mixed fuel, the control apparatus of the internal combustion engine which makes it possible to improve startability, suppressing the deterioration of an emission and a fuel consumption can be provided.

It is a schematic diagram explaining an example of a structure of the control apparatus of the internal combustion engine which concerns on one embodiment of this invention. It is a graph showing the difference in the generation | occurrence | production torque by the injection mode of the fuel in a compression stroke direct injection. It is a graph showing the difference in the generated torque by the ignition timing of the fuel in a compression stroke direct injection. It is a graph showing the relationship between the molar concentration of vaporized gasoline, ethanol, and ethanol mixed gasoline and the infrared transmittance at two different wavelengths. It is a schematic diagram showing an example of the mounting form of the optical sensor which comprises the vaporization amount detection means with which the control apparatus of the internal combustion engine which concerns on one embodiment of this invention is provided. It is a typical graph explaining the difference by the fuel of the change of the pressure (cylinder pressure) in a combustion chamber accompanying the vaporization of fuel. It is a typical graph which compares the infrared rays transmittance | permeability in a predetermined | prescribed wavelength range with ethanol of a gaseous phase state, and ethanol of a liquid phase state. It is a flowchart explaining the flow of the various processes performed in the control apparatus of the internal combustion engine which concerns on one embodiment of this invention.

  As described above, an object of the present invention is to provide a control device for an internal combustion engine that can improve startability while suppressing deterioration of emission and fuel consumption in an internal combustion engine that operates with a mixed fuel. And

  As a result of diligent research to achieve the above object, the present inventor has accurately grasped the vaporization amount of the mixed fuel in the combustion chamber, and the vaporization amount required for the ignition of the mixed fuel in the combustion chamber. If the amount is insufficient, the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber is increased by controlling the injection amount and / or ignition timing of the mixed fuel, and the amount of vaporization is excessive with respect to the required amount of vaporization In some cases, the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber is reduced by controlling the injection amount and / or ignition timing of the mixed fuel, thereby reducing emissions and fuel consumption in an internal combustion engine operated by the mixed fuel. The present inventors have found that it is possible to improve startability while suppressing the present invention and have come up with the present invention.

That is, the first embodiment of the present invention is:
An injection means that operates by a mixed fuel including a first fuel component and a second fuel component having a boiling point higher than that of the first fuel component, and that directly injects the mixed fuel into a combustion chamber; An internal combustion engine control device for controlling an internal combustion engine comprising ignition means for igniting the mixed fuel in a combustion chamber,
A vaporization amount detecting means for detecting or estimating the vaporization amount of the first fuel component and the vaporization amount of the second fuel component in the combustion chamber;
A surplus vaporization amount obtained by subtracting the required vaporization amount required for ignition of the mixed fuel in the combustion chamber from the vaporization amount of the mixed fuel detected or estimated by the vaporization amount detection means is predetermined. If it is less than the first threshold, control either or both of the injection means and the ignition means to increase the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber,
When the excess vaporization amount is equal to or greater than a predetermined second threshold value that is greater than the first threshold value, the mixed fuel in the combustion chamber is controlled by controlling either or both of the injection means and the ignition means. Reduce the amount of vaporization at the time of ignition,
A control device for an internal combustion engine.

  As described above, the control device for an internal combustion engine according to the present embodiment operates with the mixed fuel including the first fuel component and the second fuel component having a boiling point higher than the boiling point of the first fuel component, In addition, the control device of the internal combustion engine controls an internal combustion engine that includes an injection unit that directly injects the mixed fuel into a combustion chamber and an ignition unit that ignites the mixed fuel in the combustion chamber. That is, the internal combustion engine to which the control device for an internal combustion engine according to this embodiment is applied is a spark ignition direct injection internal combustion engine. The configuration of the spark ignition type direct injection internal combustion engine is well known to those skilled in the art, and is not specifically described herein.

  The mixed fuel is not particularly limited as long as it satisfies the condition that the internal combustion engine can be operated and the boiling point of the first fuel component is higher than the boiling point of the second fuel component, and can be any combination of fuel components. May be. Examples of such a mixed fuel include a combination of gasoline as the first fuel component and alcohol as the second fuel component. More specific examples of such a mixed fuel include, for example, a combination of gasoline as the first fuel component and ethanol (ethyl alcohol) as the second fuel component. The mixed fuel may contain a small amount of additives in addition to the fuel component.

  As described above, the boiling point of the second fuel component (eg, ethanol) is higher than the boiling point of the first fuel component (eg, gasoline). In other words, the second fuel component (for example, ethanol) has a lower evaporation characteristic at a lower temperature than the first fuel component (for example, gasoline). Accordingly, the engine temperature is lower when the mixed fuel containing the first fuel component and the second fuel component is used than when the fuel containing only the first fuel component is used. There is a tendency for the startability of the internal combustion engine to deteriorate (for example, during cold start).

  Therefore, in the technical field, as described above, the injection timing of the mixed fuel is adjusted according to the content of the high-boiling point fuel component (for example, ethanol) in the mixed fuel (for example, ethanol-mixed gasoline), and the compression stroke is performed. It has been proposed to improve the startability of the internal combustion engine by injecting fuel into the combustion chamber that has become high temperature and high pressure near the top dead center (direct injection in the cylinder) to promote the vaporization of the mixed fuel ( For example, see Patent Document 1). Also in such an internal combustion engine, in order to reliably improve startability while suppressing deterioration of emissions and fuel consumption, the amount of vaporization of the mixed fuel (first fuel component and second fuel component) in the combustion chamber is accurately grasped. Therefore, it is important to control so that the minimum amount of fuel required to start the internal combustion engine is supplied to the combustion chamber.

  However, as described above, in the internal combustion engine according to the related art that operates by the mixed fuel, the amount of the mixed fuel (the first fuel component and the second fuel component) in the combustion chamber is not the vaporized amount but the vaporized fuel before the vaporization ( For example, the fuel injection amount is controlled based on the content of the high boiling point fuel component (for example, ethanol) in the mixed fuel stored in the fuel tank). In other words, in an internal combustion engine according to the prior art that operates with a mixed fuel, the amount of vaporized mixed fuel (amount of vaporization) that actually contributes to the operation of the internal combustion engine is accurately grasped, and deterioration of emissions and fuel consumption is suppressed. However, it has not been possible to reliably improve the startability.

  On the other hand, the control device for an internal combustion engine according to the present embodiment includes a vaporization amount detection means for detecting or estimating the vaporization amount of the first fuel component and the vaporization amount of the second fuel component in the combustion chamber of the internal combustion engine. The vaporization amount detection means is not particularly limited as long as it can detect or estimate the vaporization amount of the first fuel component and the vaporization amount of the second fuel component in the combustion chamber of the internal combustion engine, and is a detection means having any configuration. There may be. As a specific example of the vaporization amount detecting means, for example, the vaporization amount of the first fuel component and the vaporization amount of the second fuel component are detected based on the light transmittance (for example, infrared transmittance) of the mixed gas in the combustion chamber. Or means for estimating, means for detecting or estimating the vaporization amount of the first fuel component and the vaporization amount of the second fuel component based on the pressure in the combustion chamber (in-cylinder pressure), and the like can be mentioned (details of the vaporization amount detection means) Will be described later).

  The control apparatus for an internal combustion engine according to the present embodiment having such a vaporization amount detecting means provides a vaporization amount of the mixed fuel in which the required vaporization amount required for ignition of the mixed fuel in the combustion chamber is detected or estimated by the vaporization amount detection means. (Hereinafter, sometimes referred to as “detected vaporization amount”) If the excess vaporization amount obtained by subtraction is less than a predetermined first threshold value, either or both of the injection means and the ignition means are The amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber is increased. Conversely, when the surplus vaporization amount is equal to or greater than a predetermined second threshold value that is greater than the first threshold value, the control device for the internal combustion engine according to the present embodiment provides both or one of the injection means and the ignition means. The amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber is reduced. Thereby, in the control device for an internal combustion engine according to the present embodiment, the amount of vaporized mixed fuel (vaporization amount) that actually contributes to the operation of the internal combustion engine is accurately grasped, and the deterioration of emission and fuel consumption is suppressed. In addition, the startability can be reliably improved.

  The required vaporization amount is, for example, the relationship between the temperature of the internal combustion engine, the content of the second fuel component in the vaporized mixed fuel, and the vaporization amount of the mixed fuel required for ignition of the mixed fuel in the combustion chamber. As a data table (for example, a map) that is obtained in advance by experiment, simulation, etc. and defines the correspondence between these, for example, a control device that controls fuel injection (for example, an ECU for controlling an internal combustion engine). When calculating the surplus vaporization amount stored in the data storage means provided, for example, the temperature of the internal combustion engine, the content of the second fuel component in the vaporized mixed fuel, etc. The vaporization amount of the mixed fuel required for ignition can be specified by reading from the data table. As described above, the excess vaporization amount can be obtained by subtracting the required vaporization amount required for ignition of the mixed fuel in the combustion chamber from the detected vaporization amount.

  As described above, the control device for an internal combustion engine according to the present embodiment, when the surplus vaporization amount obtained by subtracting the required vaporization amount from the detected vaporization amount is less than a predetermined first threshold, And / or the ignition means is controlled to increase the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber. That is, in other words, the first threshold is a reference for determining whether or not to increase the vaporization amount at the time of ignition of the mixed fuel in the combustion chamber. Generally, the amount of fuel vapor detected in the combustion chamber (detected vaporization amount) is smaller than the vaporization amount required for ignition (required vaporization amount) (the detected vaporization amount is insufficient with respect to the required vaporization amount) In this case, in order to improve the startability of the internal combustion engine, it is necessary to increase the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber. Therefore, in general, the first threshold value can be a negative value. The specific value of the first threshold value can be set as appropriate in consideration of, for example, the balance between the degree of startability improvement in the internal combustion engine and the degree of emission and fuel consumption deterioration.

  On the other hand, when the surplus vaporization amount is equal to or larger than a predetermined second threshold value larger than the first threshold value, as described above, the control device for the internal combustion engine according to the present embodiment includes both the injection means and the ignition means. Either one is controlled to reduce the vaporization amount at the time of ignition of the mixed fuel in the combustion chamber. That is, in other words, the second threshold is a reference for determining whether or not to reduce the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber. Generally, the amount of fuel vapor detected in the combustion chamber (detected vaporization amount) is larger than the vaporization amount required for ignition (required vaporization amount) (the detected vaporization amount is excessive with respect to the required vaporization amount) In this case, in order to suppress the deterioration of the emission and fuel consumption of the internal combustion engine, it is necessary to reduce the vaporization amount at the time of ignition of the mixed fuel in the combustion chamber. Therefore, in general, the second threshold value can be a positive value. The specific value of the second threshold value can be appropriately set in consideration of, for example, the balance between the degree of startability improvement in the internal combustion engine and the degree of emission and fuel consumption deterioration.

  As described above, the control device for an internal combustion engine according to the present embodiment controls both or one of the injection means and the ignition means to increase the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber. Or reduce. Specifically, for example, the mixed fuel injected into the combustion chamber by the injection unit is increased or decreased, or the ignition timing by the ignition unit is retarded or advanced to extend the period from injection of mixed fuel to ignition, or By shortening, the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber can be increased or decreased. The degree of increase or decrease of the injection amount of the mixed fuel by the injection unit and the degree of retard or advance of the ignition timing by the ignition unit are, for example, the magnitude of the excess vaporization amount, the excess vaporization amount and a threshold value (first threshold value). Alternatively, it can be appropriately determined according to the magnitude of the difference from the second threshold).

  As described above, in the control device for an internal combustion engine according to the present embodiment, the vaporization amount detection means detects the vaporization amount (required vaporization amount) of the mixed fuel required for ignition of the mixed fuel in the combustion chamber. Or when the estimated vaporization amount of the mixed fuel (vaporization amount of the mixed fuel that actually contributes to the operation of the internal combustion engine) (detected vaporization amount) becomes insufficient beyond a certain level (the surplus vaporization amount is smaller than the first threshold value) In the case), by controlling either or both of the injection means and the ignition means, the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber is increased, and conversely, the detected vaporization amount is less than the required vaporization amount. If it exceeds a certain amount (when the surplus vaporization amount is larger than the second threshold value), the injection means and / or the ignition means are controlled so that the mixed fuel in the combustion chamber is ignited. Reduced vaporization That.

  As described above, in the control apparatus for an internal combustion engine according to the present embodiment, as described above, the high-boiling point fuel component (for example, ethanol) in the mixed fuel (for example, the mixed fuel stored in the fuel tank) before being vaporized. The amount of vaporized mixed fuel that actually contributes to the operation of the internal combustion engine, unlike the conventional internal combustion engine that controls the fuel injection amount based on the mixing ratio of the low boiling point fuel component (for example, gasoline) Based on the (vaporization amount), the vaporization amount of the mixed fuel in the combustion chamber can be accurately controlled. As a result, in the control device for an internal combustion engine according to this embodiment, the startability can be more reliably improved while suppressing the deterioration of emission and fuel consumption.

  Here, the control apparatus for an internal combustion engine according to the present embodiment will be described in detail below with reference to the accompanying drawings. FIG. 1 is a schematic diagram illustrating an example of the configuration of the control device for an internal combustion engine according to one embodiment of the present invention as described above. An internal combustion engine 10 to which the control device for an internal combustion engine according to the embodiment shown in FIG. 1 is applied is a piston reciprocating internal combustion engine, and an intake valve, a fuel injection valve (in-cylinder injection valve) 11 and the like will be described below. It is configured as follows.

  The intake valve is a general intake valve having at least an umbrella portion. This intake valve is driven in the same manner as a general intake valve. More specifically, the umbrella portion opens and closes the intake port opening. The intake port opening is defined as “the combustion chamber is defined so that the combustion chamber defined by the“ top surface of the piston, the wall surface of the cylinder bore, and the lower surface of the cylinder head ”communicates with the intake port formed in the cylinder head. This is an opening formed on the “lower surface of the cylinder head” (that is, the end of the intake port facing the combustion chamber).

  This intake valve has a lift amount of “0” when the umbrella portion is seated on a valve seat portion formed around the intake port opening, that is, the amount of movement of the umbrella portion (the amount of movement of the intake valve). When closed, close the intake port opening. Further, the intake valve is moved so that the umbrella portion protrudes into the combustion chamber. The lift amount increases from “0” to “maximum lift amount” and then decreases from “maximum lift amount” to “0”. In a period when the lift amount is not “0”, that is, an “intake valve opening period” in which the umbrella part is away from the valve seat part, the umbrella part opens the intake port opening.

  The fuel injection valve 11 has a nozzle hole exposed in the combustion chamber. The fuel injection valve 11 is a cylinder injection valve that directly injects fuel into the combustion chamber from the injection hole by opening in response to an injection instruction signal. The fuel injection valve 11 is in a fuel injection direction that is in a direction that intersects one specific plane including the central axis of the cylinder bore and that has a component in a direction from the lower surface of the cylinder head toward the top surface of the piston. Fuel is injected.

  A fuel supply passage communicates with the fuel injection valve 11, and fuel is supplied from a fuel tank 16 (not shown) by a fuel pump 15 disposed in the middle of the fuel supply passage through the fuel supply passage. Is supplied. In addition to the fuel pump 15, the fuel supply passage includes a fuel property sensor 24 that detects a mixing ratio of the first fuel component and the second fuel component in the mixed fuel supplied from the fuel tank 16, and a fuel pump 15. A fuel pressure sensor 28 that detects the pressure of the fuel supplied to the fuel injection valve 11 is provided.

  An intake system communicates with the intake port. The intake system includes an intake pipe including an intake manifold that communicates with the intake port and forms an intake passage with the intake port, and an air provided at an end of the intake pipe. A filter (not shown), a throttle valve 14 in the intake pipe and having a variable opening cross-sectional area of the intake passage, a throttle valve actuator (not shown) comprising a DC motor constituting throttle valve driving means, and pressure in the intake pipe An intake pipe pressure sensor 22 for detecting the intake air temperature, and an intake air temperature sensor 23 for detecting the intake air temperature.

  On the other hand, an exhaust system communicates with the exhaust port. This exhaust system communicates with the exhaust port, an exhaust manifold, an exhaust pipe (exhaust pipe) (not shown) connected to the exhaust manifold, and exhaust gas purification. A catalyst (for example, an upstream three-way catalyst and a downstream three-way catalyst) (not shown) is provided. The exhaust port, the exhaust manifold, and the exhaust pipe (not shown) constitute an exhaust passage. The exhaust port is provided with an exhaust temperature sensor for detecting the exhaust temperature.

  Furthermore, the internal combustion engine 10 includes an ignition plug (ignition plug) 12 as ignition means for igniting the mixed fuel in the combustion chamber and an ignition coil 13 that generates a high voltage to be applied to the ignition plug 12. A vaporization component amount sensor 27 for detecting the vaporization amount of the first fuel component and the second fuel component constituting the mixed fuel in the combustion chamber is disposed beside the spark plug 12. In addition, the internal combustion engine 10 includes a rotation angle sensor 21 that detects the rotation angle of the crank and an engine water temperature sensor 25 that detects the temperature of the cooling water of the internal combustion engine 10.

  The electronic control unit (ECU) 20 stores, for example, a central processing unit (CPU: Central Processing Unit) connected to each other by a bus, a routine (program) executed by the CPU, a table (lookup table, map), a constant, and the like in advance. Data storage means (for example, ROM: Read Only Memory), a random access storage device (RAM: Random Access Memory) in which the CPU temporarily stores data as necessary, and stores data while the power is on. In addition, the microcomputer includes a backup RAM that holds stored data even while the power is shut off, and an interface (not shown) including an AD converter.

  The interface is configured to supply signals from the various sensors described above to the CPU. Further, the interface sends a drive signal to an intake valve drive device and a throttle valve actuator (both not shown) of each cylinder in response to an instruction from the CPU, and sends an injection instruction signal to the fuel injection valve 11 of each cylinder. The ignition signal is sent to an igniter (not shown) of each cylinder.

  As described above, the control device for the internal combustion engine according to the embodiment shown in FIG. 1 is the amount of vaporization of the mixed fuel in the combustion chamber of the internal combustion engine 10 (that is, the amount of vaporization of the first fuel component constituting the mixed fuel and the second amount). A vaporization component amount sensor 27 for detecting a fuel component vaporization amount) is provided. As a result, in the control apparatus for an internal combustion engine according to the present embodiment, the amount of vaporized mixed fuel (vaporization amount) that actually contributes to the operation of the internal combustion engine 10 can be accurately grasped. Startability can be reliably improved while suppressing deterioration.

  Specifically, the control apparatus for an internal combustion engine according to the embodiment shown in FIG. 1 reads out the required vaporization amount required for ignition of the mixed fuel in the combustion chamber of the internal combustion engine 10 from the data storage means provided in the ECU 20, and vaporizes it. The surplus vaporization amount is calculated by subtracting the required vaporization amount from the vaporization amount of the mixed fuel detected by the vaporization component amount sensor 27 as the amount detection means. Such arithmetic processing can be executed by the CPU, for example, according to a program stored in advance in data storage means provided in the ECU 20.

  Next, when the excess vaporization amount obtained as described above is less than a predetermined first threshold value, either or both of the fuel injection valve 11 as the injection means and the spark plug 12 as the ignition means. Is controlled to increase the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber. On the other hand, when the excess vaporization amount is equal to or larger than a predetermined second threshold value that is larger than the first threshold value, the fuel injection valve 11 as the injection means and / or the spark plug 12 as the ignition means are controlled. Thus, the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber is reduced.

  As described above, the control device for the internal combustion engine according to the embodiment shown in FIG. 1 is able to reduce the high boiling point fuel component (for example, ethanol) and the low fuel in the mixed fuel (for example, the mixed fuel stored in the fuel tank) before vaporization. Unlike conventional internal combustion engines that control the fuel injection amount based on the mixing ratio with the boiling point fuel component (for example, gasoline), the amount of vaporized mixed fuel that actually contributes to the operation of the internal combustion engine (vaporization amount) ), The amount of vaporization of the mixed fuel in the combustion chamber can be accurately controlled. As a result, the control apparatus for an internal combustion engine according to the embodiment shown in FIG. 1 can improve startability more reliably while suppressing deterioration of emissions and fuel consumption.

  As described above, the specific configuration of the vaporization component amount sensor 27 includes, for example, the vaporization amount of the first fuel component based on the light transmittance (for example, infrared transmittance) of the mixed gas in the combustion chamber. The configuration for detecting or estimating the vaporization amount of the second fuel component, the configuration for detecting or estimating the vaporization amount of the first fuel component and the vaporization amount of the second fuel component based on the pressure in the combustion chamber (in-cylinder pressure), etc. (Details of the vaporization amount detection means will be described later).

  In the above, in order to facilitate understanding of the present invention, the amount of fuel vaporized in the combustion chamber of the internal combustion engine 10 (that is, the amount of vaporized first fuel component and the second fuel component constituting the fuel mixture). The vaporization amount detection is performed to detect or estimate the vaporization amount of the mixed fuel in the combustion chamber as in the vaporization component amount sensor 27. The amount of vaporization of the mixed fuel in the combustion chamber (that is, vaporization of the first fuel component constituting the mixed fuel) using not only the detection result by the means but also the detection result by other detection means such as the fuel property sensor 24, for example. And the amount of vaporization of the second fuel component) may be detected or estimated.

  As described above, the configuration of the control device for an internal combustion engine according to one embodiment of the present invention has been described with reference to FIG. 1, but FIG. 1 is only for the internal combustion engine according to one embodiment of the present invention. The configuration shown in FIG. 1 is shown for the purpose of facilitating understanding of the control device, and is merely an illustrative example of the configuration of the control device for an internal combustion engine according to one embodiment of the present invention. Therefore, the configuration of the control device for the internal combustion engine according to the present embodiment should not be construed as being limited to the configuration shown in FIG.

  By the way, in the control device for an internal combustion engine according to the present embodiment, as described above, the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber is controlled by controlling both or one of the injection means and the ignition means. Adjust. That is, in the control device for an internal combustion engine according to the present embodiment, the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber may be adjusted by controlling both the injection unit and the ignition unit, or the injection unit The vaporization amount at the time of ignition of the mixed fuel in the combustion chamber may be adjusted by controlling either one of the means and the ignition means.

  In the case where the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber is increased by controlling the injection means, in the control device for the internal combustion engine according to the present embodiment, for example, the mixed fuel injected into the combustion chamber by the injection means By increasing the amount, the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber can be increased.

That is, the second embodiment of the present invention is:
A control device for an internal combustion engine according to the first embodiment of the present invention, comprising:
When the surplus vaporization amount is less than the first threshold value, the vaporization amount at the time of ignition of the mixed fuel in the combustion chamber is increased by increasing the amount of the mixed fuel injected into the combustion chamber by the injection means. Increase the
A control device for an internal combustion engine.

  As described above, in the control device for an internal combustion engine according to the present embodiment, the amount of the mixed fuel injected into the combustion chamber by the injection unit is increased when the excessive vaporization amount is less than the first threshold value. Thus, the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber is increased. Thereby, the control apparatus for an internal combustion engine according to the present embodiment can increase the vaporization amount of the mixed fuel in the combustion chamber when the detected vaporization amount exceeds a certain amount with respect to the required vaporization amount. As a result, in the control device for an internal combustion engine according to this embodiment, the startability can be more reliably improved while suppressing the deterioration of emission and fuel consumption.

  The method for increasing the amount of the mixed fuel injected into the combustion chamber by the injection means is not particularly limited. For example, the injection period is extended by the injection means, the opening of the injection nozzle of the injection means is increased, the injection pressure of the mixed fuel is increased. Due to the rise or the like, the amount of the mixed fuel injected into the combustion chamber by the injection means can be increased.

  Conversely, in the case where the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber is reduced by controlling the injection means, in the control device for the internal combustion engine according to the present embodiment, for example, the injection means is injected into the combustion chamber. By reducing the amount of the mixed fuel, the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber can be reduced.

That is, the third embodiment of the present invention
A control device for an internal combustion engine according to the first embodiment of the present invention, comprising:
The amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber by reducing the amount of the mixed fuel injected into the combustion chamber by the injection means when the surplus vaporization amount is equal to or greater than the second threshold. Decrease,
A control device for an internal combustion engine.

  As described above, in the control apparatus for an internal combustion engine according to the present embodiment, when the excessive vaporization amount is equal to or greater than the second threshold value, the mixed fuel injected into the combustion chamber by the injection unit is reduced. As a result, the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber is reduced. Thereby, the control apparatus for an internal combustion engine according to the present embodiment can reduce the vaporization amount of the mixed fuel in the combustion chamber when the detected vaporization amount exceeds a certain amount with respect to the required vaporization amount. As a result, in the control device for an internal combustion engine according to the present embodiment, it is possible to suppress deterioration of emissions and fuel consumption while ensuring startability.

  The method for reducing the amount of the mixed fuel injected into the combustion chamber by the injection means is not particularly limited. For example, the injection period is shortened by the injection means, the opening of the injection nozzle of the injection means is reduced, the injection pressure of the mixed fuel is Due to the decrease or the like, the mixed fuel injected into the combustion chamber by the injection means can be reduced.

  As described above, in the technical field, the injection timing of the mixed fuel is adjusted according to the content of the high-boiling point fuel component (for example, ethanol) in the mixed fuel (for example, ethanol-mixed gasoline), and the compression stroke is performed. It has been proposed to improve the startability of the internal combustion engine by injecting fuel into the combustion chamber that has become high temperature and high pressure near the top dead center (direct injection in the cylinder) to promote the vaporization of the mixed fuel ( For example, see Patent Document 1). Thus, when fuel is injected into the combustion chamber in the compression stroke (compression cylinder direct injection), for example, the injection timing is retarded or the mixed fuel is injected at least twice per cycle (divided) Or the like), the vaporization of the mixed fuel can be further promoted.

  Here, the above will be described in detail below with reference to the accompanying drawings. FIG. 2 is a graph showing the difference in generated torque depending on the fuel injection mode in the direct injection in the compression stroke as described above. In FIG. 2, the correspondence between the fuel injection amount and the torque generated per cycle of the internal combustion engine when the in-cylinder injection is performed at a standard timing as the compression stroke in-cylinder direct injection is represented by black circles. . On the other hand, when the in-cylinder injection is performed at a timing delayed by 20 ° from the standard timing as the direct injection in the compression stroke, the fuel injection amount is represented by a black square mark. And the torque generated per cycle of the internal combustion engine are shifted to the high torque side, and the rate of change of torque (ie, the slope of the graph) with respect to the change in the fuel injection amount is also increased. In addition, in the case of performing in-cylinder injection in which fuel injection is performed twice, that is, standard timing for direct injection in the compression stroke and timing delayed by 20 ° from the standard timing, As shown by the white squares, the correspondence relationship between the fuel injection amount and the torque generated per cycle of the internal combustion engine is further shifted to the higher torque side, and the torque against the change in the fuel injection amount The rate of change (that is, the slope of the graph) is further increased.

  As described above, in the compression stroke direct injection, fuel vaporization is promoted by retarding the injection timing or by split injection, and higher torque can be generated with a smaller amount of fuel. As a result, the required injection amount when trying to generate the same torque can be reduced by performing retarded injection timing or split injection in the compression stroke direct injection.

  Note that the vaporization of the mixed fuel is further promoted by retarding the injection timing in the compression stroke direct injection as described above, for example, the pressure in the combustion chamber at the time of fuel injection and the delay of the injection timing. This is considered to be caused by a higher temperature. In particular, when the high boiling point fuel component (second raw material component) in the mixed fuel is a fuel containing oxygen (for example, in the molecular structure) (oxygen-containing fuel), the injection timing may be retarded as described above. Since the fuel can be burned by diffusion combustion, this tendency is more remarkable. Further, as described above, vaporization of the mixed fuel is further promoted by dividing and injecting the fuel into a plurality of times in the direct injection in the compression stroke (divided injection). It is considered that the fuel injected into the room is diffused during the period until the next injection, and the fuel concentration in the space region where the fuel is injected by the next injection is reduced.

  Thus, not only the amount of fuel injected into the combustion chamber but also the pressure and temperature in the combustion chamber at the time of fuel injection and the injection mode (for example, split injection, Fluctuates by batch injection). Therefore, from this point of view, in order to achieve the object of the present invention to improve the startability while suppressing the deterioration of the emission and the fuel consumption in the internal combustion engine operated by the mixed fuel, it actually contributes to the operation of the internal combustion engine. It can be seen that it is important to accurately grasp the amount of vaporized fuel mixture (vaporization amount).

  By the way, when performing split injection as described above, for example, the amount of fuel vaporized in the combustion chamber after the first injection in split injection (that is, the amount of vaporization of the first fuel component and the second fuel constituting the fuel mixture) By adjusting the second and subsequent injection amounts in the split injection based on the component vaporization amount), the total amount of vaporized mixed fuel that actually contributes to the operation of the internal combustion engine can be controlled more accurately.

  For example, in the case of performing split injection as described above, the vaporization amount of the mixed fuel in the combustion chamber after the first injection in the split injection (that is, the vaporization amount of the first fuel component and the second fuel component constituting the mixed fuel) Is detected or estimated by the vaporization amount detecting means, and the vaporization amount thus obtained is required for ignition of the mixed fuel in the combustion chamber after the first injection from the (detected vaporization amount). By subtracting the required vaporization amount, the excess vaporization amount of the mixed fuel in the combustion chamber after the first injection can be calculated. If the surplus vaporization amount thus obtained is less than a predetermined first threshold value, the injection means is controlled to increase the injection amount of the second and subsequent mixed fuels, which actually contributes to the operation of the internal combustion engine. The total amount of vaporized mixed fuel to be increased can be increased. On the other hand, when the surplus vaporization amount is equal to or greater than a predetermined second threshold value that is greater than the first threshold value, the injection means is controlled to reduce the injection amount of the second and subsequent mixed fuels. The total amount of vaporized fuel mixture that actually contributes to operation can be reduced.

That is, the fourth embodiment of the present invention is
An internal combustion engine control apparatus according to the second embodiment of the present invention, comprising:
After the first injection of the divided injection executed by the injection means and before the second injection, the injection means executes the divided injection for injecting the fuel at least twice per cycle. By increasing the amount of the mixed fuel injected into the combustion chamber in the second and subsequent injections of the divided injection when the excess vaporization amount in the combustion chamber at the time of is less than the first threshold value, Increasing the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber;
A control device for an internal combustion engine.

In addition, the fifth embodiment of the present invention provides:
A control apparatus for an internal combustion engine according to the third embodiment of the present invention, comprising:
After the first injection of the divided injection executed by the injection means and before the second injection, the injection means executes the divided injection for injecting the fuel at least twice per cycle. When the surplus vaporization amount in the combustion chamber at the time of is less than or equal to the second threshold value, the mixed fuel injected into the combustion chamber in the second and subsequent injections of the divided injection is reduced, Reducing the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber;
A control device for an internal combustion engine.

  Incidentally, in a spark ignition type internal combustion engine, ignition is generally performed after compression top dead center. However, for example, when using a mixed fuel containing a high boiling point fuel component (for example, alcohol mixed fuel), when the engine temperature is low (for example, during cold start, etc.), fuel vaporization is insufficient. Because the period required for the fuel to ignite becomes long, even if the ignition timing is advanced before the top dead center (TDC), ignition occurs at an appropriate timing, and sufficient torque can be generated. There is a case.

  Here, the above will be described in detail below with reference to the accompanying drawings. FIG. 3 is a graph showing the difference in the generated torque depending on the fuel ignition timing in the compression stroke direct injection as described above. In FIG. 3, the correspondence between the fuel injection amount and the torque generated per cycle of the internal combustion engine when ignition is performed at standard timing as direct injection in the compression stroke (that is, ignition after TDC) Expressed with a mark. On the other hand, when ignition is performed at a timing advanced by 5 ° from the standard timing as direct injection in the compression stroke (ignition before TDC), as shown by the white diamond mark, The correspondence relationship between the injection amount of the engine and the torque generated per cycle of the internal combustion engine is shifted to the high torque side. Further, when ignition is performed at a timing advanced by 10 ° from the standard timing as direct injection in the compression stroke (ignition before TDC), fuel injection is performed as indicated by white triangles. The correspondence relationship between the amount and the torque generated per cycle of the internal combustion engine is further shifted to the higher torque side (see the arrow in the figure).

  As described above, in the direct injection in the compression stroke, higher torque can be generated with a smaller amount of fuel as the ignition timing advances. As a result, the required injection amount when attempting to generate the same torque can be reduced by advancing the ignition timing in the direct compression cylinder direct injection. On the other hand, the ignition of the fuel in the combustion chamber can be facilitated by retarding the ignition timing. This is considered to be caused by delaying the ignition timing by the ignition means, extending the period from injection of the mixed fuel to ignition, and increasing the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber. It is done. Thus, it can be seen that the amount of vaporization at the time of ignition of fuel in the combustion chamber also varies depending on the ignition timing by the ignition means.

  By the way, in some embodiments described so far, as a method for increasing or decreasing the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber, the injection means is controlled and the injection means injects into the combustion chamber. The method of increasing or decreasing the amount of the mixed fuel is adopted. However, as described above, the method of increasing or decreasing the vaporization amount at the time of ignition of the mixed fuel in the combustion chamber increases or decreases the mixed fuel injected into the combustion chamber by the injection means as in these embodiments. It is not limited to the method to do.

  Specifically, as described above, in the control device for an internal combustion engine according to the present invention, for example, the ignition timing by the ignition means is retarded or advanced to extend or shorten the period from the injection of the mixed fuel to the ignition. As a result, the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber can be increased or decreased. In this case, the degree of retardation or advance of the ignition timing by the ignition means depends on, for example, the magnitude of the excess vaporization amount, the magnitude of the difference between the excess vaporization amount and the threshold value (first threshold value or second threshold value). Can be determined as appropriate.

That is, the sixth embodiment of the present invention
A control device for an internal combustion engine according to the first embodiment of the present invention, comprising:
When the surplus vaporization amount is less than the first threshold value, the ignition timing for igniting the mixed fuel in the combustion chamber is retarded by the ignition means, thereby igniting the mixed fuel in the combustion chamber. Increase the amount of vaporization,
A control device for an internal combustion engine.

In addition, the seventh embodiment of the present invention provides
A control device for an internal combustion engine according to the first embodiment of the present invention, comprising:
When the surplus vaporization amount is equal to or greater than the second threshold value, the ignition timing for igniting the mixed fuel in the combustion chamber is advanced by the ignition means, so that at the time of ignition of the mixed fuel in the combustion chamber Reduce the amount of vaporization,
A control device for an internal combustion engine.

  By the way, in the control device for an internal combustion engine according to some embodiments described so far, the excessive vaporization amount is less than the first threshold (the detected vaporization amount exceeds the required vaporization amount beyond a certain level). In the case where the excess vaporization amount is equal to or greater than the second threshold value (the detected vaporization amount exceeds the required vaporization amount beyond a certain level), the vaporization amount at the time of ignition of the mixed fuel in the combustion chamber is increased or increased. By reducing the amount, the startability is improved while suppressing deterioration of emission and fuel consumption. As a modification of this embodiment, in addition to increasing or decreasing the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber, the energy of spark discharge when igniting the mixed fuel in the combustion chamber is increased or decreased. Thus, the startability can be improved while controlling the ignitability of the mixed fuel in the combustion chamber and suppressing the deterioration of the emission and fuel consumption.

That is, the eighth embodiment of the present invention is
A control device for an internal combustion engine according to the first embodiment of the present invention, comprising:
The ignition means is a spark ignition type spark plug that ignites the mixed fuel by a spark discharge between electrodes;
The mixed fuel combusted in the combustion chamber by increasing the energy of spark discharge when the mixed fuel in the combustion chamber is ignited by the ignition means when the surplus vaporization amount is less than the first threshold value. Increase the amount of the
A control device for an internal combustion engine.

The ninth embodiment of the present invention provides
A control device for an internal combustion engine according to the first embodiment of the present invention, comprising:
The ignition means is a spark ignition type spark plug that ignites the mixed fuel by a spark discharge between electrodes;
The mixed fuel combusted in the combustion chamber by reducing the energy of spark discharge when the mixed fuel in the combustion chamber is ignited by the ignition means when the surplus vaporization amount is equal to or greater than the second threshold value. Reduce the amount of
A control device for an internal combustion engine.

  As described above, the control device for an internal combustion engine according to these embodiments includes the spark ignition type spark plug that ignites the mixed fuel by spark discharge between the electrodes as the ignition means. In addition, in the control apparatus for an internal combustion engine according to these embodiments, when the excessive vaporization amount is less than the first threshold value or when the excessive vaporization amount is equal to or greater than the second threshold value, an ignition plug as an ignition means is used. By increasing or decreasing the energy of the spark discharge when igniting the mixed fuel in the combustion chamber, the amount of the mixed fuel combusted in the combustion chamber can be increased or decreased. Thereby, in the control apparatus for an internal combustion engine according to these embodiments, the startability can be more reliably improved while suppressing the deterioration of emission and fuel consumption.

  By the way, as described above, the control apparatus for an internal combustion engine according to the present invention includes a vaporization amount detection means for detecting or estimating the vaporization amount of the first fuel component and the vaporization amount of the second fuel component in the combustion chamber of the internal combustion engine. . The vaporization amount detection means is not particularly limited as long as it can detect or estimate the vaporization amount of the first fuel component and the vaporization amount of the second fuel component in the combustion chamber of the internal combustion engine, and the detection means having any configuration. It may be. As this vaporization amount detection means, for example, the vaporization amount of the first fuel component and the vaporization amount of the second fuel component are detected or estimated based on the light transmittance (for example, infrared transmittance) of the mixed gas in the combustion chamber. Means can be mentioned.

  Specifically, when a means for detecting or estimating the vaporization amount of the first fuel component and the vaporization amount of the second fuel component based on the light transmittance of the mixed gas in the combustion chamber is employed as the vaporization amount detection means, such vaporization is performed. As the quantity detection means, the light transmittance at at least two or more wavelengths of the mixed gas in the combustion chamber is measured, and based on the light transmittance thus measured (at each wavelength), the first in the combustion chamber is measured. The vaporization amount of the fuel component and the vaporization amount of the second fuel component can be estimated.

That is, the tenth embodiment of the present invention is
An internal combustion engine control apparatus according to any one of the first to ninth embodiments of the present invention,
The vaporization amount detection means measures the light transmittance of at least two or more wavelengths of the mixed gas in the combustion chamber, and based on the light transmittance thus measured, the first fuel component in the combustion chamber The amount of vaporization and the amount of vaporization of the second fuel component are estimated,
A control device for an internal combustion engine.

  As described above, in the control device for an internal combustion engine according to the present embodiment, the vaporization amount detecting means measures the light transmittance at at least two wavelengths of the mixed gas in the combustion chamber, and thus measures the light transmittance. Based on the transmitted light transmittance, the vaporization amount of the first fuel component and the vaporization amount of the second fuel component in the combustion chamber are estimated. More specifically, in the control device for an internal combustion engine according to the present embodiment, the light transmittance at at least two wavelengths of the mixed gas in the combustion chamber is measured by the vaporization amount detection means.

On the other hand, the extinction coefficients at the respective wavelengths of the first fuel component and the second fuel component constituting the mixed fuel are obtained in advance by, for example, experiments. As is well known to those skilled in the art, the light transmittance at each wavelength, the extinction coefficient of the first fuel component and the second fuel component, and the distance through which the light used for measuring the light transmittance is transmitted, for example, by fitting to the Lambert-Beer law (Lambert-Beer law), Ru can be calculated the concentrations of the first fuel component and a second fuel component. Thereby, according to the control device for an internal combustion engine according to the present embodiment, it is possible to accurately grasp the amount of vaporized mixed fuel (vaporization amount) that actually contributes to the operation of the internal combustion engine. Startability can be reliably improved while suppressing deterioration.

  Here, with respect to the ethanol-mixed gasoline obtained by mixing gasoline as the first fuel component and ethanol as the second fuel component, the procedure for obtaining the gasoline and ethanol concentrations by the above method will be described below with reference to the accompanying drawings. Explained. FIG. 4 is a graph showing the relationship between the molar concentration of vaporized gasoline, ethanol, and ethanol-mixed gasoline and the infrared transmittance at two different wavelengths as described above. That is, in the example shown in FIG. 4, infrared light is used as light used for measuring light transmittance. Also, in FIG. 4, the correspondence between vaporization molar concentration and infrared transmittance in the case of gasoline (100%) is represented by square marks, and the correspondence between vaporization molar concentration and infrared transmittance in the case of ethanol (100%). Is represented by a circle, and the correspondence relationship between the vaporized molar concentration and the infrared transmittance in the case of ethanol mixed gasoline (20/80) is represented by a triangle. Moreover, the black plot represents the infrared transmittance in the 2.7 μm band, and the white plot represents the infrared transmittance in the 3.4 μm band.

  As shown in FIG. 4, in any wavelength band, there was a tendency for the infrared transmittance to decrease as the vaporization molar concentration increased. In addition, in any of vaporized gasoline, ethanol, and ethanol mixed gasoline, the infrared transmittance in the 3.4 μm band is lower than the infrared transmittance in the 2.7 μm band, and the change in vaporized molar concentration It was observed that the rate of change (the rate of decrease in infrared transmittance relative to the increase in vaporization molar concentration) was large.

  Further, regarding the infrared transmittance in the 2.7 μm band, the rate of change with respect to the change in the vaporization molar concentration of ethanol (the rate of decrease in the infrared transmittance with respect to the increase in the vaporized molar concentration) The ethanol blended gasoline shows these intermediate behaviors, which is larger than the decrease rate of the infrared transmittance with respect to the increase in vaporization molarity. On the other hand, for the infrared transmittance in the 3.4 μm band, the rate of change with respect to the change in the vaporization molar concentration of ethanol (the rate of decrease in the infrared transmittance with respect to the increase in the vaporized molar concentration) is the change with respect to the change in the vaporization molar concentration of gasoline. Compared to the rate (decreasing rate of infrared transmission with increasing vaporization molarity), ethanol blended gasoline shows these intermediate behaviors.

  From the above, it can be seen that the vapor extinction coefficient in the 3.4 μm band is larger than the molar extinction coefficient in the 2.7 μm band in any of the vaporized gasoline and ethanol. It can also be seen that ethanol has a larger molar extinction coefficient than gasoline in the 2.7 μm band and ethanol has a smaller molar extinction coefficient than gasoline in the 3.4 μm band.

  As described above, the light transmittance in each wavelength band reflects the blending ratio and vaporization molar concentration of gasoline and ethanol in the mixed fuel. For example, as described above, gasoline and ethanol in each wavelength band. The light transmission coefficient of each of the wavelengths actually measured, the absorption coefficient of gasoline and ethanol, and the distance through which the light used for the measurement of the light transmission is transmitted are determined by Lambert. By applying Beer's law, it is possible to calculate the vapor concentration of each of gasoline and ethanol.

Here, an example of a procedure for calculating the vaporization molar concentrations of gasoline and ethanol will be further described below with reference to mathematical expressions. First, the molar concentrations of gasoline and ethanol in the gas to be measured are C _g and C _e , respectively. The molar extinction coefficient of gasoline and ethanol in the 2.7 μm band is ε _{(2.7, g)} and ε _{(2.7, e),} and the molar extinction coefficient in the 3.4 μm band is ε _{(3.4, g ) And} ε _{(3.4, e)} . Furthermore, the infrared transmittances measured in the 2.7 μm band and the 3.4 μm band are (I / I ₀ ) _(2.7) and (I / I ₀ ) _{(3.4), respectively,} and are subject to measurement. Let L be the distance through which the infrared rays pass through the gas. At this time, the following equation (1) is established based on Lambert-Beer's law.

The unknown in the above formula (1) is only the molar concentration of gasoline and ethanol (C _g and C _e ) in the gas to be measured. Therefore, by calculating a binary simultaneous linear equation obtained by substituting a known number into the above equation (1), the molar concentrations of gasoline and ethanol (C _g and C _e ) in the gas to be measured are calculated. Can do.

As shown in FIG. 4, in the 2.7 μm band, the change rate of the infrared transmittance with respect to the change in the vaporization molar concentration of gasoline (the decrease rate of the infrared transmittance with respect to the increase in the vaporization molar concentration) is the vaporization of ethanol. It is extremely small compared with the change rate of the infrared transmittance with respect to the change of the molar concentration (the decrease rate of the infrared transmittance with respect to the increase of the vaporization molar concentration), and can be regarded as substantially 0 (zero). In such a case, the molar absorption coefficient ε _{(2.7, g)} in the 2.7 μm band of gasoline is considered to be 0 (zero), so that the measurement target is obtained from the first equation of the above equation (1). calculating the molar concentration C _e of ethanol in the gas, the molar concentration C _e of ethanol that is computed by Thus by substituting the second equation of the equation (1), the molar concentration of gasoline in a gas to be measured C _g may be calculated.

  Here, referring to the attached drawings, an example of a mounting form of an optical sensor (vaporization component amount sensor) (for example, an infrared sensor) that constitutes a vaporization amount detection means provided in the control device for an internal combustion engine according to the present embodiment, This will be described below. FIG. 5 is a schematic diagram showing an example of the mounting form of the optical sensor constituting the vaporization amount detecting means provided in the control device for an internal combustion engine according to one embodiment of the present invention as described above. In the example shown in FIG. 5, the optical sensor is mounted so that the light transmittance in the vicinity of the electrode of the spark plug is measured.

  Specifically, as shown in FIG. 5, light (for example, infrared rays) emitted from a light source is guided to the vicinity of the electrode of the spark plug through an optical fiber. Therefore, light guided through the optical fiber (hereinafter sometimes referred to as “light-emitting optical fiber”) is emitted into the combustion chamber from the end of the light-emitting optical fiber opposite to the light source. On the other hand, in the vicinity of the electrode of the spark plug, in addition to the above-mentioned “light emitting optical fiber”, a light receiving unit that receives light emitted from the end of the light emitting optical fiber into the combustion chamber and detects the transmitted light intensity (for example, An end portion of another optical fiber (hereinafter sometimes referred to as “light receiving optical fiber”) for leading to an infrared detecting portion is provided. In addition, the process in which the light emitted from the end of the light emitting optical fiber opposite to the light source reaches the end of the light emitting optical fiber opposite to the light receiving unit is described with respect to the above formula (1). Corresponds to the distance L. In FIG. 5, the light emitted from the end of the light-emitting optical fiber is reflected by the mirror and guided to the end of the light-receiving optical fiber.

  Accordingly, the optical sensor shown in FIG. 5 is detected after the mixed fuel is injected into the combustion chamber of the internal combustion engine with respect to the light transmission intensity detected before the mixed fuel is injected into the combustion chamber of the internal combustion engine. The light transmittance of the mixed fuel vaporized in the combustion chamber (specifically, near the electrode of the spark plug) can be obtained from the ratio of the light transmission intensity. In addition, the structure of the optical sensor which comprises the vaporization amount detection means with which the control apparatus of the internal combustion engine which concerns on this embodiment is provided is not limited to the said description, The light of the mixed fuel vaporized in the combustion chamber in a desired wavelength band Any configuration is possible as long as the transmittance can be obtained. Furthermore, the light used for the measurement of the light transmittance is not limited to infrared rays, and for example, light belonging to other wavelength regions such as ultraviolet rays and visible light may be used.

  By the way, as described above, the control device for an internal combustion engine according to the present embodiment measures the light transmittance of at least two or more wavelengths of the mixed gas in the combustion chamber, and thus based on the measured light transmittance. Thus, the vaporization amount of the first fuel component (for example, gasoline) and the second fuel component (for example, ethanol) constituting the mixed fuel in the combustion chamber of the internal combustion engine are calculated. However, not only the detection result by the vaporization amount detection means for detecting or estimating the vaporization amount of the mixed fuel in the combustion chamber in this way, but also the mixing ratio of the first fuel component and the second fuel component in the mixed fuel before vaporization is determined. The detection result of the mixture ratio detecting means (for example, a fuel property sensor that detects the mixture ratio of the first fuel component and the second fuel component in the mixed fuel supplied from the fuel tank) is also used to detect the mixture in the combustion chamber. The vaporization amount of the mixed fuel in (i.e., the vaporization amount of the first fuel component and the vaporization amount of the second fuel component constituting the mixed fuel) may be detected or estimated.

That is, the eleventh embodiment of the present invention is
An internal combustion engine control apparatus according to any one of the first to ninth embodiments of the present invention,
And further comprising a mixture ratio detecting means for detecting or estimating a mixture ratio of the first fuel component and the second fuel component in the mixed fuel before being injected into the combustion chamber,
The vaporization amount detecting means measures the light transmittance at one wavelength of the mixed gas in the combustion chamber,
The vaporization amount of the first fuel component and the second fuel component in the combustion chamber based on the mixture ratio detected or estimated by the mixture ratio detection unit and the light transmittance measured by the vaporization amount detection unit Estimate the amount of vaporization of
A control device for an internal combustion engine.

  As described above, the control apparatus for an internal combustion engine according to the present embodiment detects or estimates the mixing ratio of the first fuel component and the second fuel component in the mixed fuel before being injected into the combustion chamber. A ratio detection unit, wherein the vaporization amount detection unit measures the light transmittance at one wavelength of the mixed gas in the combustion chamber, and the mixture ratio and the vaporization amount detected or estimated by the mixture ratio detection unit Based on the light transmittance measured by the detection means, the vaporization amount of the first fuel component and the vaporization amount of the second fuel component in the combustion chamber are estimated. In an internal combustion engine that operates with a mixed fuel, a mixture ratio detecting means for detecting a mixing ratio between the first fuel component and the second fuel component in the mixed fuel (for example, the first fuel component in the mixed fuel supplied from the fuel tank) In general, a fuel property sensor or the like that detects a mixing ratio with the second fuel component is provided in, for example, a fuel tank, a fuel supply passage, or the like. Examples of the fuel property sensor include a capacitance type alcohol sensor.

  Therefore, as the vaporization amount detection means provided in the control device for an internal combustion engine according to this embodiment, it is sufficient to provide a vaporization amount detection means capable of measuring the light transmittance at one wavelength of the mixed gas in the combustion chamber. Therefore, in the control apparatus for an internal combustion engine according to the present embodiment, for example, the amount of vaporized mixed fuel that actually contributes to the operation of the internal combustion engine while suppressing problems such as a complicated configuration and an increase in manufacturing cost. By accurately grasping (vaporization amount), it is possible to reliably improve startability while suppressing deterioration of emissions and fuel consumption.

Here, based on the light transmittance at one wavelength of the mixed gas in the combustion chamber and the mixing ratio of the first fuel component and the second fuel component in the mixed fuel before injection, the mixed fuel vaporized in the combustion chamber An example of a procedure for calculating the approximate molar concentration will be further described below with reference to mathematical expressions. In this example, the infrared transmittance (I / I ₀ ) _(3.4) in the 3.4 μm band and the moles of gasoline as the first fuel component and ethanol as the second fuel component in the mixed fuel before injection. Based on the ratio (1-p: p), the approximate molar concentration of the mixed fuel vaporized in the combustion chamber is calculated.

First, even when vaporized in the combustion chamber, the molar ratio of gasoline to ethanol is assumed to be the same as the molar ratio of the mixed fuel before injection (before vaporization). The coefficient ε _{(3.4, c)} is expressed by the following equation (2).

In the above equation, ε _{(3.4, g)} and ε _{(3.4, e)} are molar extinction coefficients in the 3.4 μm band of gasoline and ethanol vaporized in the combustion chamber. Accordingly, the molar concentration C _c of the mixed fuel vaporized in the combustion chamber in this case is expressed by the following equation (3) based on the Lambert-Beer law.

However, in practice, ethanol, which is the second fuel component having a relatively high boiling point, is difficult to vaporize, and has a relatively low boiling point, particularly in the initial stage when the engine temperature is low (for example, during cold start). It is considered that gasoline as the first fuel component is mainly vaporized. That is, the molar concentration C _c of the mixed fuel is calculated as described above are likely to include an error. Specifically, the amount of ethanol vaporization in the initial stage is slight, and it is considered that the true molar ratio p ₀ of the mixed fuel vaporized in the combustion chamber is smaller than the molar ratio p of ethanol in the mixed fuel before injection. . As described above, in the 3.4 μm band, gasoline has a larger molar extinction coefficient than ethanol (ε _{(3.4, g)} > ε _{(3.4, e)} ). Thus, the true and the molar concentration C _c of the mixed fuel is calculated as described above, the mixed fuel (ethanol blended gasoline) vaporized in the combustion chamber, a first fuel component (gasoline), and a second fuel component (ethanol) The relationship shown in the following formula (4) is established between the molar concentrations of C _c0 , C _g0 , and C _e0 .

On the other hand, only gasoline to vaporize initially, when ethanol is assumed not vaporized, the molar concentration C _g gasoline vaporized in the combustion chamber is represented by the following equation (5).

In practice, however, ethanol is vaporized even in a small amount, contributing to a decrease in infrared transmittance. Therefore, the molar concentration C _{g of} gasoline calculated by the equation (5) is calculated as a larger value compared with the true molar concentration C _g0 of gasoline vaporized in the combustion chamber (C _g > C _g0 ). . However, as mentioned above, only gasoline to vaporize initially, since ethanol would not vaporized, at least initially, the molar concentration C _g petrol calculated by Equation (5), the combustion chamber It is considered that there is no significant difference from the true molar concentration C _g0 of gasoline vaporized in (C _{g ≈C g0} ).

By the way, when the amount of the mixed fuel injected into the combustion chamber by the injection means is q, the ratio (molar ratio) of gasoline is 1-p, and vaporization is performed in the combustion chamber using these values. The maximum molar concentration C _gmax of gasoline to be obtained can be calculated. Thus, C _gmax is the maximum molar concentration of gasoline that can be vaporized in the combustion chamber. Thus, equation (5) When the molar concentration _{C g} gasoline calculated exceeds the maximum molar concentration _{C gmax} gasoline by _{(C g> C gmax),} the excess is the infrared transmittance with ethanol as described above It can be considered that the error is due to the contribution to the decrease.

Therefore, the maximum molar concentration values obtained by subtracting the C _gmax gasoline from the molar concentration C _c of the mixed fuel is calculated by Equation (3) described above is defined to correspond to the molar concentration C _e of ethanol vaporized in the combustion chamber ( _{C e = C c -C gmax)} . And the molar concentration C _e of ethanol obtained by thus, from the sum of the molar concentration C _g petrol calculated by Equation (5) can calculate the molar concentration of the mixed fuel that has vaporized in the combustion chamber . In the present specification, the molar concentration of the mixed fuel thus obtained is expressed as “C _c ′” (that is, C _g + C _e = C _c ′).

Since the true molar concentration C _c0 of the mixed fuel (ethanol mixed gasoline) vaporized in the combustion chamber falls between the molar concentrations C _c and C _c ′ of the two mixed fuels described above, the moles of these two mixed fuels Based on the smaller value of the concentrations C _c and C _c ′, the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber is appropriately controlled to ensure startability while suppressing deterioration of emissions and fuel consumption. Can be improved.

As described above, in the 2.7 μm band, the molar absorption coefficient ε _{(2.7, g)} of gasoline can be regarded as substantially 0 (zero). the control apparatus for an internal combustion engine according from the first equation of equation (1) described above, to calculate the molar concentration C _e of ethanol in the gas to be measured, the molar concentration of ethanol is calculated thus C _e Based on the above, the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber may be controlled.

  By the way, as described above, the light used for the measurement of the light transmittance is not limited to infrared rays, and for example, light belonging to other wavelength regions such as ultraviolet rays and visible light may be used. Among these, infrared light is preferable as light used for measuring light transmittance.

That is, the twelfth embodiment of the present invention is
A control device for an internal combustion engine according to any one of the tenth or eleventh embodiments of the present invention,
The light used to measure the light transmittance of the mixed gas in the combustion chamber is infrared;
A control device for an internal combustion engine.

  By the way, as described above, the control device for an internal combustion engine according to the present embodiment includes a vaporization amount detection means for detecting or estimating the vaporization amount of the first fuel component and the vaporization amount of the second fuel component in the combustion chamber of the internal combustion engine. Prepare. The vaporization amount detection means is not particularly limited as long as it can detect or estimate the vaporization amount of the first fuel component and the vaporization amount of the second fuel component in the combustion chamber of the internal combustion engine, and is a detection means having any configuration. There may be. As a specific example of the vaporization amount detecting means, for example, as described above, the vaporization amount of the first fuel component and the second fuel component of the second fuel component are based on the light transmittance (for example, infrared transmittance) of the mixed gas in the combustion chamber. In addition to means for detecting or estimating the amount of vaporization, examples include means for detecting or estimating the amount of vaporization of the first fuel component and the amount of vaporization of the second fuel component based on the pressure in the combustion chamber (cylinder pressure).

That is, the thirteenth embodiment of the present invention is
An internal combustion engine control apparatus according to any one of the first to ninth embodiments of the present invention,
A mixture ratio detecting means for detecting or estimating a mixture ratio of the first fuel component and the second fuel component in the mixed fuel before being injected into the combustion chamber;
In-cylinder pressure detecting means for detecting or estimating the pressure in the combustion chamber;
Further comprising
Based on the mixture ratio detected or estimated by the mixture ratio detection means, the vaporization latent heat of the mixed fuel before being injected into the combustion chamber is calculated,
Based on the difference between the pressure in the combustion chamber detected or estimated by the in-cylinder pressure detecting means when the mixed fuel is injected and the pressure in the combustion chamber when the mixed fuel is not injected, Calculating a temperature change in the combustion chamber accompanying vaporization of the mixed fuel;
Based on the vaporization latent heat of the mixed fuel thus calculated and the temperature change in the combustion chamber, the vaporization amount of the mixed fuel in the combustion chamber is estimated.
A control device for an internal combustion engine.

  As described above, the control apparatus for an internal combustion engine according to the present embodiment detects or estimates the mixing ratio of the first fuel component and the second fuel component in the mixed fuel before being injected into the combustion chamber. The apparatus further comprises ratio detection means and in-cylinder pressure detection means for detecting or estimating the pressure in the combustion chamber. Since the mixing ratio detection means has already been described in the description of the control device for an internal combustion engine according to another embodiment of the present invention, description thereof will be omitted here. On the other hand, the in-cylinder pressure detecting means is not particularly limited as long as the pressure in the combustion chamber can be detected or estimated, and may have any configuration. Examples of such in-cylinder pressure detecting means include in-cylinder pressure detecting means using a piezoelectric element type pressure sensor.

  Further, as described above, the control device for an internal combustion engine according to the present embodiment is configured to control the mixed fuel before being injected into the combustion chamber based on the mixture ratio detected or estimated by the mixture ratio detection unit. Based on the difference between the pressure in the combustion chamber detected or estimated by the in-cylinder pressure detecting means when the mixed fuel is injected and the pressure in the combustion chamber when the mixed fuel is not injected, by calculating the latent heat of vaporization. And calculating a temperature change in the combustion chamber accompanying the vaporization of the mixed fuel in the combustion chamber, and based on the thus calculated latent heat of vaporization of the mixed fuel and a temperature change in the combustion chamber. The amount of vaporization of the mixed fuel in the room is estimated.

  In other words, the control apparatus for an internal combustion engine according to the present embodiment is configured as the entire mixed fuel from the mixing ratio of the first fuel component (for example, gasoline) and the second fuel component (for example, ethanol) constituting the mixed fuel. The temperature change accompanying vaporization of the mixed fuel is calculated from the difference between the pressure in the combustion chamber when the mixed fuel is not injected and the pressure in the combustion chamber when the mixed fuel is injected. Thus, the vaporization amount of the mixed fuel in the combustion chamber is calculated from the temperature change and the latent heat of vaporization thus calculated.

  In the above, the latent heat of vaporization of the mixed fuel is, for example, a data table (for example, a map) that preliminarily obtains the latent heat of vaporization of the mixed fuel having various mixing ratios through experiments or the like and defines the correspondence between the mixing ratio and the latent heat of vaporization. ) And the like, for example, stored in a data storage means provided in a control device (for example, an ECU for controlling the internal combustion engine) for controlling fuel injection, and the vaporization latent heat of the mixed fuel is calculated as described above. In this case, the latent heat of vaporization corresponding to the mixture ratio detected or estimated by the mixture ratio detection means can be specified by reading from the data table.

  Next, as described above, the control device for an internal combustion engine according to the present embodiment is configured such that when the mixed fuel is injected, the pressure in the combustion chamber detected or estimated by the in-cylinder pressure detecting means and the mixed fuel are not injected. Based on the difference from the pressure in the combustion chamber, the temperature change in the combustion chamber accompanying the vaporization of the mixed fuel in the combustion chamber is calculated. Here, as for the pressure in the combustion chamber when the mixed fuel is not injected, for example, an in-cylinder pressure in a state where the fuel is not injected into the combustion chamber is obtained in advance by an experiment, and a control device (for example, controlling the fuel injection) For example, when the temperature change in the combustion chamber accompanying the vaporization of the mixed fuel in the combustion chamber is calculated as described above, Can be read from the data table.

  The control apparatus for an internal combustion engine according to this embodiment detects or estimates the pressure in the combustion chamber when the mixed fuel obtained as described above is not injected and the in-cylinder pressure detecting means when the mixed fuel is injected. The difference between the pressure in the combustion chamber is calculated, and the temperature change in the combustion chamber accompanying the vaporization of the mixed fuel in the combustion chamber is calculated based on the difference. As is well known to those skilled in the art, in calculating the temperature change from the pressure difference in this way, an operation based on thermodynamic consideration can be used.

  The control device for an internal combustion engine according to the present embodiment estimates the vaporization amount of the mixed fuel in the combustion chamber based on the latent heat of vaporization of the mixed fuel calculated as described above and the temperature change in the combustion chamber. In the above-described method, the vaporization amount of the mixed fuel is estimated by paying attention to changes in temperature and pressure accompanying the mixed fuel injected into the combustion chamber taking vaporization latent heat from the air in the combustion chamber. The mixed fuel injected into the combustion chamber contacts not only the air in the combustion chamber but also the wall side (cylinder inner wall surface) of the combustion chamber. However, since the temperature of the cylinder inner wall surface is low under conditions where the engine temperature is low (for example, during cold start), sufficient accuracy can be ensured even by the method described above.

Here, the difference of the change in the pressure in the combustion chamber (cylinder pressure) due to the vaporization of the fuel due to the fuel will be described with reference to the accompanying drawings. FIG. 6 is a schematic graph for explaining the difference between the changes in the pressure in the combustion chamber (in-cylinder pressure) due to fuel vaporization, as described above, depending on the fuel. Specifically, FIG. 6 is a schematic graph for explaining the difference in the pressure in the combustion chamber (cylinder pressure) associated with the vaporization of gasoline and ethanol. As shown in FIG. 6, when gasoline having a relatively small vaporization latent heat is used as fuel even if fuel of the same molar concentration is injected into the combustion chamber, ethanol having a relatively large vaporization latent heat is used as the fuel. Compared to the case, it can be seen that the decrease in the in-cylinder pressure (in-container pressure) accompanying the increase in the elapsed time after the start of fuel injection (elapsed time after the start of injection) is smaller (ΔP _g <ΔP _e ).

This is because the latent heat of vaporization of gasoline is smaller than the latent heat of vaporization of ethanol. Therefore, the combustion chamber accompanying the vaporization of gasoline is compared with the decrease in the temperature of the combustion chamber (cylinder temperature) associated with the vaporization of ethanol. As a result, the decrease in the in-cylinder pressure due to gasoline vaporization (ΔP _g ) is smaller than the decrease in the in-cylinder pressure due to ethanol vaporization (ΔP _e ). Is considered to be smaller. As described above, the decrease in the in-cylinder pressure accompanying the vaporization of the fuel reflects the latent heat of vaporization of the material constituting the fuel. Based on this phenomenon, the amount of fuel vaporization can be determined from the change in the in-cylinder pressure accompanying the fuel vaporization.

  By the way, as described above, the mixed fuel used for operating the internal combustion engine to which the control device for the internal combustion engine according to the present invention is applied can operate the internal combustion engine and can be the first fuel component. As long as the condition that the boiling point of is higher than the boiling point of the second fuel component is satisfied, there is no particular limitation, and any combination of fuel components may be used. Examples of such a mixed fuel include a combination of gasoline as the first fuel component and alcohol as the second fuel component. More specific examples of such a mixed fuel include, for example, a combination of gasoline as the first fuel component and ethanol (ethyl alcohol) as the second fuel component.

Accordingly, the fourteenth embodiment of the present invention provides:
An internal combustion engine control apparatus according to any one of the first to thirteenth embodiments of the present invention,
The first fuel component is gasoline;
A control device for an internal combustion engine.

The fifteenth embodiment of the present invention is
An internal combustion engine control apparatus according to any one of the first to fourteenth embodiments of the present invention,
The second fuel component is alcohol;
A control device for an internal combustion engine.

Furthermore, the sixteenth embodiment of the present invention provides
A control device for an internal combustion engine according to the fifteenth embodiment of the present invention, comprising:
The second fuel component is ethanol;
A control device for an internal combustion engine.

  As described above, the mixed fuel may contain a small amount of additives in addition to the fuel component.

  By the way, as described above, the control apparatus for an internal combustion engine according to various embodiments of the present invention described so far detects the required vaporization amount required for ignition of the mixed fuel in the combustion chamber by the vaporization amount detection means. When the surplus vaporization amount obtained by subtracting from the estimated vaporization amount of the mixed fuel is less than a predetermined first threshold value, both or any one of the injection means and the ignition means are controlled, and the combustion chamber In the case where the amount of vaporization at the time of ignition of the mixed fuel is increased and the excess vaporization amount is equal to or larger than a predetermined second threshold value which is larger than the first threshold value, either or both of the injection means and the ignition means To control the amount of vaporization at the time of ignition of the mixed fuel in the combustion chamber.

  The control apparatus for an internal combustion engine according to the modified example of the present invention vaporizes at the time of ignition of the mixed fuel in the combustion chamber according to the degree of deviation between the excess vaporization amount and the threshold value (first threshold value and second threshold value). The amount control may be configured to be executed more finely. Specifically, the control device for an internal combustion engine according to one modification of the present invention further sets, for example, a third threshold value smaller than the first threshold value and a fourth threshold value smaller than the third threshold value, When the surplus vaporization amount is less than the first threshold value and is equal to or greater than the third threshold value (that is, the difference between the surplus vaporization amount and the threshold value is small), the mixed fuel in the combustion chamber is only retarded by retarding the ignition timing. When the amount of vaporization at the time of ignition is increased and the excess vaporization amount is less than the third threshold value and greater than or equal to the fourth threshold value (that is, the difference between the excess vaporization amount and the threshold value is medium), the ignition timing In addition to increasing the amount of fuel injected by the injection means, the amount of fuel vaporization at the time of ignition of the fuel mixture in the combustion chamber is increased, and the surplus gasification amount is less than the fourth threshold (that is, surplus). Large discrepancy between vaporization amount and threshold B) In the case does not perform ignition in the cycle may be configured so as to ignite the mixed fuel by performing the ignition in the next cycle.

  An internal combustion engine to which the control device for an internal combustion engine according to the present invention is applied is an internal combustion engine that uses both in-cylinder direct injection and intake port injection (hereinafter sometimes referred to as a “combined internal combustion engine”). Also good. Furthermore, in the combined internal combustion engine, the amount of the second fuel component (for example, ethanol) in the intake port is estimated to identify the amount of the second fuel component that remains as a liquid phase in the intake port. It is also possible to control the fuel injection amount by direct in-cylinder injection based on the estimated adhesion amount.

  As a means for estimating the adhesion amount of the second fuel component (for example, ethanol) in the intake port, for example, the light transmittance in a predetermined wavelength band (for example, 2.9 μm, 1.55 μm, etc.) is measured. And an optical sensor. FIG. 7 is a schematic graph comparing the infrared transmittance in a predetermined wavelength band between ethanol in a gas phase and ethanol in a liquid phase as described above. As shown in FIG. 7, the infrared transmittance of ethanol in the gas phase (open square mark) is almost 1, whereas the infrared transmittance of ethanol in the liquid phase (black square mark). Is significantly reduced.

  As described above, the second fuel component (for example, ethanol) in the intake port is utilized by utilizing the fact that the infrared transmittance in a predetermined wavelength band varies greatly depending on the phase of the second fuel component (for example, ethanol). Can be estimated. Therefore, as described above, by controlling the fuel injection amount by in-cylinder direct injection based on the adhesion amount thus estimated, it is possible to suppress the deterioration of emission and fuel consumption in the internal combustion engine that operates with the mixed fuel. In addition, the startability can be improved.

  Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. However, the following description is for illustrative purposes only, and the scope of the present invention should not be construed as being limited to the following description.

  Here, the flow of various processes executed in the control apparatus for an internal combustion engine according to one embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 8 is a flowchart illustrating the flow of various processes executed in the control device for an internal combustion engine according to one embodiment of the present invention as described above. In the present embodiment, a case will be described in which the control device for an internal combustion engine according to the present embodiment is applied to an internal combustion engine that directly injects mixed fuel into the cylinder in two steps in the compression stroke.

  As shown in FIG. 8, first, in step 101, when the ignition switch is turned on (ON) and the control of the fuel vaporization amount by the control device for the internal combustion engine according to this embodiment is started, the next step 102 is performed. In the mixed fuel supplied from the fuel tank, for example, by a mixture ratio detecting means using a fuel property sensor (for example, a capacitance type alcohol sensor) disposed in a fuel tank, a fuel supply passage, etc. A mixing ratio between the first fuel component and the second fuel component is detected. In step 103, the cooling means temperature (engine water temperature) and the air temperature of the internal combustion engine are detected by the detection means using an engine water temperature sensor, an intake air temperature sensor, and the like. Next, in step 104, fuel injection conditions and ignition conditions are determined based on the fuel mixture ratio and each temperature detected as described above. In step 105, the required vaporization amount required for ignition of the mixed fuel in the combustion chamber is set based on the fuel mixture ratio and each temperature detected as described above.

  As described above, the required vaporization amount is necessary for, for example, the temperature of the internal combustion engine (engine water temperature), the content of the second fuel component (fuel mixture ratio) in the vaporized mixed fuel, and the ignition of the mixed fuel in the combustion chamber. For example, fuel injection is controlled as a data table (for example, a map) that predetermines the relationship with the vaporization amount of the mixed fuel to be determined in advance by, for example, experiments or simulations. It can be specified by storing in a data storage means provided in a control device (for example, ECU for controlling the internal combustion engine) and reading out from the data table as necessary.

  Next, cranking is started in step 106, and the first fuel injection is executed at a predetermined time in step 107. Next, at step 108, the amount of fuel vaporization in the combustion chamber (in-cylinder vaporization amount) at a predetermined time before ignition is detected. In step 109, a calculation process is performed to subtract the required vaporization amount calculated in step 105 from the in-cylinder vaporization amount (detected vaporization amount) detected in step 108, and the excess vaporization amount is calculated.

  Next, at step 110, it is determined whether or not the excess vaporization amount is less than a first threshold value. When the excess vaporization amount is less than the first threshold (step 110: Yes), the second fuel injection is increased in step 111. Further, in step 112, the ignition timing may be retarded. On the other hand, when the excessive vaporization amount is equal to or greater than the first threshold value (step 110: No), it is determined in step 113 whether the excessive vaporization amount is equal to or greater than the second threshold value. If the excess vaporization amount is equal to or greater than the second threshold (step 113: Yes), the second fuel injection is reduced in step 114. On the other hand, when the excessive vaporization amount is less than the second threshold value (step 113: No), in step 115, the second injection is executed with the injection conditions and ignition conditions determined in step 104 being maintained.

  Further, in step 116, ignition is performed, and the mixed fuel injected into the combustion chamber is ignited. Finally, in step 117, the control of the amount of vaporization of the mixed fuel by the control device for the internal combustion engine according to this embodiment is completed. . Thus, according to the control apparatus for an internal combustion engine according to the present embodiment, the startability can be improved while suppressing deterioration of the emission and fuel consumption in the internal combustion engine operated by the mixed fuel.

  The embodiment shown in the present embodiment is only one embodiment of the present invention shown for illustrative purposes only, and the control device for an internal combustion engine according to the present invention is limited by the description in the present embodiment. Should not be interpreted.

  Although several embodiments having specific configurations have been described above for the purpose of illustrating the present invention, the scope of the present invention is not limited to these exemplary embodiments, and patents Needless to say, modifications can be made as appropriate within the scope of the claims and the description of the specification.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... In-cylinder injection valve, 12 ... Spark plug, 13 ... Ignition coil, 14 ... Throttle valve, 15 ... Fuel pump, 16 ... Fuel tank, 20 ... ECU, 21 ... Rotation angle sensor, 22 ... Intake air Pipe pressure sensor, 23 ... intake air temperature sensor, 24 ... fuel property sensor, 25 ... engine water temperature sensor, 27 ... vaporized component amount sensor, and 28 ... fuel pressure sensor.

Claims (13)

An injection means that operates by a mixed fuel including a first fuel component and a second fuel component having a boiling point higher than that of the first fuel component, and that directly injects the mixed fuel into a combustion chamber; and controlling an internal combustion engine having an ignition means for igniting the fuel mixture in the combustion chamber, 1 divided into at least twice per cycle Ru split injection for injecting fuel is performed in the injection means, the engine control device Because
A vaporization amount detecting means for detecting or estimating the vaporization amount of the first fuel component and the vaporization amount of the second fuel component in the combustion chamber;
The required vaporization amount required for ignition of the mixed fuel in the combustion chamber at the time after the first injection of the divided injection executed by the injection means and before the second injection When the surplus vaporization amount obtained by subtracting from the vaporization amount of the mixed fuel detected or estimated by the detection means is less than a predetermined first threshold value , the combustion in the second and subsequent injections of the divided injection by increasing the amount of the mixed fuel to be injected into the combustion chamber and, Ru increases the amount of vaporization at the time of ignition of the fuel mixture in the combustion chamber,
Control device for internal combustion engine. A control device for an internal combustion engine according to claim 1,
When the surplus vaporization amount is equal to or greater than a predetermined second threshold value that is greater than the first threshold value, by reducing the amount of the mixed fuel injected into the combustion chamber in the second and subsequent injections of the divided injection reduces the amount of vaporization at the time of ignition of the fuel mixture in the combustion chamber,
Control device for internal combustion engine. A control device for an internal combustion engine according to claim 1 or 2 ,
When the surplus vaporization amount is less than the first threshold value, the ignition timing for igniting the mixed fuel in the combustion chamber is retarded by the ignition means, thereby igniting the mixed fuel in the combustion chamber. Increase the amount of vaporization,
Control device for internal combustion engine. A control device for an internal combustion engine according to claim 1 or 2 ,
When the surplus vaporization amount is equal to or greater than the second threshold value, the ignition timing for igniting the mixed fuel in the combustion chamber is advanced by the ignition means, so that at the time of ignition of the mixed fuel in the combustion chamber Reduce the amount of vaporization,
Control device for internal combustion engine. A control device for an internal combustion engine according to claim 1 or 2 ,
The ignition means is a spark ignition type spark plug that ignites the mixed fuel by a spark discharge between electrodes;
The mixed fuel combusted in the combustion chamber by increasing the energy of spark discharge when the mixed fuel in the combustion chamber is ignited by the ignition means when the surplus vaporization amount is less than the first threshold value. Increase the amount of the
Control device for internal combustion engine. A control device for an internal combustion engine according to claim 1 or 2 ,
The ignition means is a spark ignition type spark plug that ignites the mixed fuel by a spark discharge between electrodes;
The mixed fuel combusted in the combustion chamber by reducing the energy of spark discharge when the mixed fuel in the combustion chamber is ignited by the ignition means when the surplus vaporization amount is equal to or greater than the second threshold value. Reduce the amount of
Control device for internal combustion engine. The control device for an internal combustion engine according to any one of claims 1 to 6 ,
The vaporization amount detection means measures the light transmittance of at least two or more wavelengths of the mixed gas in the combustion chamber, and based on the light transmittance thus measured, the first fuel component in the combustion chamber The amount of vaporization and the amount of vaporization of the second fuel component are estimated,
Control device for internal combustion engine. The control device for an internal combustion engine according to any one of claims 1 to 6 ,
And further comprising a mixture ratio detecting means for detecting or estimating a mixture ratio of the first fuel component and the second fuel component in the mixed fuel before being injected into the combustion chamber,
The vaporization amount detecting means measures the light transmittance at one wavelength of the mixed gas in the combustion chamber,
The vaporization amount of the first fuel component and the second fuel component in the combustion chamber based on the mixture ratio detected or estimated by the mixture ratio detection unit and the light transmittance measured by the vaporization amount detection unit Estimate the amount of vaporization of
Control device for internal combustion engine. A control device for an internal combustion engine according to claim 7 or 8 ,
The light used to measure the light transmittance of the mixed gas in the combustion chamber is infrared;
Control device for internal combustion engine. The control device for an internal combustion engine according to any one of claims 1 to 6 ,
A mixture ratio detecting means for detecting or estimating a mixture ratio of the first fuel component and the second fuel component in the mixed fuel before being injected into the combustion chamber;
In-cylinder pressure detecting means for detecting or estimating the pressure in the combustion chamber;
Further comprising
Based on the mixture ratio detected or estimated by the mixture ratio detection means, the vaporization latent heat of the mixed fuel before being injected into the combustion chamber is calculated,
Based on the difference between the pressure in the combustion chamber detected or estimated by the in-cylinder pressure detecting means when the mixed fuel is injected and the pressure in the combustion chamber when the mixed fuel is not injected, Calculating a temperature change in the combustion chamber accompanying vaporization of the mixed fuel;
Based on the vaporization latent heat of the mixed fuel thus calculated and the temperature change in the combustion chamber, the vaporization amount of the mixed fuel in the combustion chamber is estimated.
Control device for internal combustion engine. A control device for an internal combustion engine according to any one of claims 1 to 10 ,
The first fuel component is gasoline;
Control device for internal combustion engine. An internal combustion engine control device according to any one of claims 1 to 11 ,
The second fuel component is alcohol;
Control device for internal combustion engine. The control apparatus for an internal combustion engine according to claim 12 ,
The second fuel component is ethanol;
Control device for internal combustion engine.

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